Myringoplasty

Myringoplasty also called tympanoplasty is microsurgical technique to reconstruct a ruptured or perforated eardrum (tympanic membrane) with the placement of a graft, either medial or lateral to the tympanic membrane annulus, often using the patient’s own tissues. The goal of this surgical procedure is not only to close the perforation but also to improve hearing. The success of the operation depends on the ability to eradicate disease from the middle ear (eg, inflamed granulation tissue and cholesteatoma). Various techniques have been developed and refined, and a number of grafting materials are available. Both the lateral and medial grafting techniques are detailed below.

Myringoplasty can be used for small perforations, such as nonhealing tympanic membranes after pressure-equalizing tube extrusion or traumatic perforations. The technique involves freshening the edges of the perforation to promote healing and placing a carefully trimmed graft lateral to the defect ¹. Grafting materials for myringoplasty include fat, Gelfilm, Gelfoam, AlloDerm, and cigarette paper. Gelfoam can also be placed as packing in the middle ear to support the graft.

Myringoplasty is a safe and effective outpatient procedure used to both eradicate disease from the middle ear and restore hearing and middle ear function ². Your child will need to stay in the hospital overnight. A number of surgical approaches and grafting techniques are available for use by the surgeon. Paramount to success are the preoperative assessment, good hemostasis intraoperatively, and thoughtful surgical planning with careful placement of the graft.

When planning myringoplasty, the surgeon must consider the location of the perforation (marginal versus central), and size (total versus subtotal). Areas of myringosclerosis and tympanosclerosis should be noted. Important comorbidities worth noting include craniofacial disorders and underlying environmental allergies or chronic allergic rhinitis. Critical factors that make myringoplasty less successful include adhesive otitis media, severe eustachian tube dysfunction with either perforation of the contralateral ear or ongoing intermittent otorrhea, cholesteatoma, and previous surgical repair ³.

Myringoplasty key points

• A myringoplasty is an operation to fix a hole in the eardrum.
• The operation usually takes about two to three hours.
• Your child will sleep and feel no pain during the operation.
• After the operation, your child will have to stay overnight in the hospital.
• While your child gets better at home, there are some things your child should not do.

Tympanic membrane anatomy

The eardrum also called tympanic membrane is a thin layer of tissue that vibrates in response to sound. An understanding of the tympanic membrane anatomy is critical to successful repair. Myringoplasty (tympanoplasty) procedure mandates an understanding of the layers. The tympanic membrane typically consists of the following 3 layers:

1. Lateral epithelial layer
2. Middle fibrous layer
3. Medial mucosal layer

The outer epithelial layer is composed of stratified squamous epithelium, which is continuous with the skin of the external auditory canal. This is significant because in-growth of this outer epithelial portion through the perforation can result in an epithelial cyst called an acquired cholesteatoma. Untreated, this cyst then releases destructive enzymes that can enlarge the size of the perforation and ultimately cause ossicular erosion. The lateral grafting technique that is discussed later in this text requires that this entire epithelial layer be stripped from the drum remnant prior to placement of the graft so as to avoid iatrogenic cholesteatoma formation.

The middle fibrous layer is composed of connective tissue consisting of outer radial fibers and inner circular fibers. It provides strength to the drum. A healed perforation is also commonly deficient of this middle fibrous layer. The epithelial and endothelial layers regenerate creating a “dimeric” membrane. This miscalculation can be corrected when carefully examined under binocular microscopy. Because this middle layer is absent in the pars flaccida superiorly, the posterior-superior aspect of the drum can be drawn inward toward the middle ear as a retraction pocket.

The inner layer of the tympanic membrane consists of simple cuboidal and columnar epithelium cells. This layer is identical to the mucosal lining of the rest of the middle ear mucosal tissue and is considered to be critical to ensure healing of tympanic membrane perforations, and the surgeon often abrades or rasps the undersurface of the tympanic membrane remnant to stimulate regrowth.

Annulus

The peripheral edge of the tympanic membrane is rimmed by a dense fibrous layer called the annulus, which is essentially a thickening of the pars tensa. Successful elevation of the annulus is critical for medial grafting technique. The annulus is deficient superiorly at the “12 o’clock” location. This area is the notch of Rivinus and can guide the surgeon to a natural plane to elevate the annulus.

Ear canal

The ear canal has bone in the medial component (inner one-third). The lateral portion, which extends into the pinna, is composed of cartilage. The boney/cartilaginous interface is located at the medial two-thirds junction. Most incisions that are made to raise a tympanomeatal flap or perform either an endaural or transcanal approaches are made at this location as well. The superiorly placed vascular strip is another critical area within the ear canal. This region is demarcated by the tympanosquamous suture line superiorly and the tympanomastoid junction line inferiorly. Canal incisions are often made along these junctions.

Middle ear

The middle ear is an air-filled space bordered by the bony labyrinth of the inner ear medially, the tympanic membrane laterally, and the cranium superiorly. This space contains the ossicles, nerves (facial nerve, chorda tympani, Jacobsen nerve), small muscles (stapedius and tensor tympani), ligaments, and blood vessels. The petrous portion of the internal carotid artery and the internal jugular vein, which are both in proximity to the middle ear space, can be dehiscent and should be noted on any preoperative imaging. Rarely, middle ear pathology can involve these structures.

In order for successful grafting of the tympanic membrane to improve hearing, an intact ossicular chain must be present. The malleus transmits energy from the tympanic membrane to the incus, which itself is connected to the stapes superstructure resting on the oval window. Diarthrodial joints connect the 3 ossicles and allow the transmission of acoustic energy from the tympanic membrane to the inner ear. The incudostapedial joint is the most fragile and, hence, has the highest likelihood to require repair.

Mastoid

The middle ear communicates with the mastoid air cells via the mastoid antrum. The temporal bone air cells are usually pneumatized by 3 years of age. However, the air cells can remain underdeveloped and sclerotic in patients with persistent eustachian tube dysfunction. A poorly pneumatized or fluid-filled mastoid bone predisposes a patient to require a more extensive tympanomastoidectomy to improve the chances of successful graft placement.

Eustachian tube

The eustachian tube connects the middle ear with the nasopharynx and allows pressure equilibration in the middle ear. Enlarged adenoids or biofilms within this lymphoid tissue are hypothesized to predispose a patient to persistent middle ear disease. This bony-cartilaginous tube is approximately 45° from the horizontal in adults but only 10° from horizontal in infants. In addition, the infant eustachian tube is about 50% of the adult length.

Inner ear

The inner ear is composed of the cochlea, which is the end-organ for hearing, and the vestibular organs. The vestibular organs include the utricle, saccule, and the 3 semicircular canals and are involved in balance.

Figure 1. Ear anatomy

Figure 2. Tympanic membrane anatomy (right ear)

Myringoplasty surgery

Myringoplasty (tympanoplasty) is an outpatient procedure for adults and for most children. The operation takes about two to three hours. Your child will need to stay in the hospital overnight.

Your child will sleep and feel no pain during the operation. Just before your child has the operation, they will be given a sleep medicine. This is called a general anesthetic. This means that your child will sleep and feel no pain during the operation.

The ear nose and throat (ENT) doctor will take a tiny piece of tissue from an area around the ear. This is done by making a cut behind your child’s ear. The piece of ear tissue is then used to fix the hole in your child’s eardrum. Your child will have dissolvable stitches behind the ear and gauze packing in the ear to absorb any fluid.

Various techniques and grafting materials can be used. Which approach is used depends on the size and location of the perforation, the presence or absence of cholesteatoma or granulation tissue, the status of the ossicles and mastoid, other anatomical considerations (eg, narrow external auditory canals), as well as the surgeon’s preference and expertise ⁴.

Examining the middle ear and ossicles and removing any elements of adhesions or cholesteatoma is critical. The chosen approach should provide optimal visualization of the perforation and tympanic membrane. One should be careful not to disrupt an intact and mobile ossicular chain if the hearing loss is only low-frequency conductive, as is often the case with hearing loss secondary to a perforation ⁵.

Before the operation

Evaluation of the patient for myringoplasty involves a detailed history and physical examination. Important aspects of the history include the duration of the perforation, severity of otalgia, otorrhea, hearing loss, vertigo, previous attempts at repair, otitis media, and otitis externa. The number and frequency of infections (including time of most recent infection) provide insight into the severity of disease. Past otologic surgical history is critical and should include any history of tympanostomy tubes (also called myringotomy tubes, ventilation tubes, or pressure equalization (PE) tubes) and details of any prior tympanoplasties (including approaches, grafts used, outcomes).

Prior to considering surgery in any patient, acute and chronic infections should be controlled using ototopical, oral, and/or intravenous antibiotics or antifungals, if indicated. Ototopical drops with steroids may also be needed if granulation tissue or aural polyps are visualized to improve inflammation. Ideally, an ear should be “dry” for 3-4 months before surgery is performed to enhance the chance of success. Individuals who undergo surgery must keep the operated ear dry for a period of several weeks or until the graft has healed. Operating on an actively infected ear is contraindicated.

Physical examination

The physical examination should focus on pneumatic otoscopy and otomicroscopy. In the office, tuning forks can give an important assessment of hearing; in older patients, tuning forks can be used to confirm audiometric findings. Additional assessments include documentation of facial nerve functionality and inspection for previous incisions. Although a small amount of cerumen is tolerated in the routine otoscopic examination, obstructive cerumen should be removed when evaluating a patient for myringoplasty in order to provide an unimpeded view of the entire tympanic membrane.

Monomeric (or more accurately, dimeric) areas may appear as perforations until inspected more closely under microscopy. Retraction pockets should be closely inspected for accumulation of squamous debris. Considering the status of the contralateral ear when considering repair of a tympanic membrane perforation is essential. The ear with more significant hearing loss is usually operated on first if bilateral perforations exist.

Audiometric testing

Audiometry should be performed preoperatively in all surgical candidates. Tympanometry can add useful information in younger children who are difficult to properly examine. The primary reason for audiometric analysis is to establish the degree of conductive hearing loss. Perforations usually cause low-frequency conductive loss ⁶. If underlying ossicular discontinuity exists and is not addressed during surgery, then postoperative hearing can be worse despite an intact neo-tympanum. One should consider ossicular involvement if the conductive hearing loss is flat across all frequencies or greater than 35 db. Finally, the presence and degree of any sensorineural hearing loss should be documented preoperatively.

Radiographic testing

Computed tomography (CT) and magnetic resonance imaging (MRI) is not essential but may be indicated in patients in whom a concern for cochlear, labyrinthine, or intracranial pathology exists. Other patients who might be considered for preoperative imaging include patients with a history of facial palsy, children with craniofacial abnormalities, and revision cases in which the anatomy may be distorted.

Pre-operative imaging assists the surgeon in preoperatively identifying pathology and planning surgery. CT scan should be ordered when concern exists for cholesteatoma and in patients with previous mastoid surgery, otalgia, or vertigo. MRI is beneficial for delineating the integrity of the dura as well as detecting small retrocochlear lesions such as acoustic neuromas.

Grafting materials

Various materials exist for use for tympanic membrane grafting. True temporalis fascia is the most common graft because of its ease of harvest and its abundant availability, even in revision cases. Some surgeons prefers loose areolar fascia (also known as “fool’s fascia”) and prefer to save the true fascia for revision cases. Also, the “fool’s fascia” is considered by some to be more pliable, have less donor site morbidity, and to be more transparent after healing. It is available via the same postauricular incision that can be used for tympanoplasty, or a separate incision can be made in or beyond the postauricular hairline if a transcanal or endaural technique is used. A mild amount of donor site morbidity occurs, with postoperative pain over the temporalis muscle being the most common symptom.

• The postauricular incision is marked and injected with lidocaine with epinephrine.
• Dissection is carried down onto the fascia (loose areolar /true temporalis).
• The graft is harvested.
• Muscle is removed from the fascia graft, and the graft is then set on the back table for later use.

Cartilage is available to be harvested easily from either the tragus or the conchal bowl, if a post-auricular approach is being used. Tragal cartilage is harvested with perichondrium attached via a small incision on the internal surface of the tragus ⁷. This graft is an appropriate size and carries very little donor site morbidity. In addition, the perichondrium can be reflected to stabilize the graft. Conchal cartilage also carries no additional significant morbidity. Other grafting materials include lobular fat, periosteum, perichondrium, vein, and AlloDerm.

Myringoplasty procedure

Transcanal approach

The transcanal approach is especially good for small posterior perforations, but can be used for medium-sized perforations if the anterior tympanic membrane is easily visualized. This technique can be challenging for significant anterior perforations, narrow/stenotic ear canals, or individuals with a significant anterior canal bulge. Inspecting the perforation prior to preparing the patient and determining that at least a 5-mm speculum can be placed is important. Canalplasty can be used to improve visualization if slightly limited.

Medial graft

When performing a transcanal medial tympanoplasty procedure, the following steps are followed:

1. The ear canal is suctioned and surgical Betadine used during the surgical prep is removed.
2. The external auditory canal is cleaned and injected with 1% lidocaine with 1:100,000 epinephrine or 0.5% lidocaine with 1:200,000 epinephrine, primarily for vasoconstriction to optimize visualization during the procedure.
3. The edge of the perforation is dissected and removed using a sharp pick and cup forceps; this “postage-stamping” and “freshening” of the perforation is critical to ensure that the graft incorporates into the native tympanic membrane remnant.
4. Next, a tympanomeatal flap is created. It is customized based on the location of the perforation and surgeon’s preference. The flap design should be such that it can be easily and atraumatically raised and the undersurface of tympanic membrane perforation can be readily accessed. A medially-based tympanomeatal flap is usually created with radial incisions at 12 o’clock and 6 o’clock (ie, superiorly and inferiorly) that either connect directly or via a semilunar incision in the posterior canal just medial to the bony-cartilaginous junction.
5. The tympanomeatal flap is raised medially with a round knife. To avoid traumatic tearing, take great care not to suction on the flap.
6. When the annulus is reached, the tympanotomy is made such that the instrument of choice (eg, round knife, gimmick, sickle knife, pick) lifts the annulus while hugging the bony groove from which the fibrous annulus can be dissected. The fibrous annulus is then dissected circumferentially with care not to injure the ossicles, the chorda tympani nerve, or residual drum. The flap is then positioned, usually anteriorly, such that the perforation is exposed.
7. A canalplasty of the posterior or anterior external auditory canal can be performed to optimize visualization. Take care not to injure the facial nerve or temporomandibular joint.
8. If indicated, the middle ear and ossicles are inspected and palpated to confirm ossicular continuity. Middle ear disease (granulation tissue, tympanosclerosis, adhesions, cholesteatoma) is completely removed. Removing hypertrophic middle ear mucosa with either a McCabe dissector or Duckbill elevator, particularly mucosa abutting the fibrous annulus in anterior tympanic membrane perforations, is important.
9. Ossicular reconstruction can be performed if necessary, followed by grafting of the perforation. Elevating the tympanic membrane remnant off the long process of the malleus with a sickle knife may be necessary. This allows both closer inspection of the ossicles and better placement of the graft.
10. The middle ear must be carefully packed with the surgeon’s preferred material – either Gelfilm, Gelfoam, or Surgicel. This is often soaked in either oxymetazoline, antibiotic ear drops, or diluted epinephrine (1:10,000). Packing the mesotympanum and hypotympanum is important, although excess packing should be avoided near the ossicles so as to prevent adhesions.
11. The graft is trimmed on the back table. The graft should adequately cover the entire defect. Hemostasis is critical to intraoperative visualization and successful placement of the graft. The graft should be well supported so as to avoid shifting or displacement.
12. Some surgeons advocate that nitrous oxide anesthetic be switched off at this point because this particular agent has a tendency to accumulate in spaces such as the middle ear and can potentially dislodge the graft.
13. The tympanomeatal flap is laid back down over the graft, and the posterior canal skin edges are laid flat. Pieces of Gelfoam, Surgicel, or antibiotic ointment are placed along the tympanic membrane and graft and layered laterally to cover the canal incisions.
14. Antibiotic ointment is placed in the lateral canal, and either Vaseline-coated or antibiotic-coated sculpted cotton ball is placed in the external auditory meatus.
15. An optional Glasscock or mastoid pressure dressing is placed at the end of the case, particularly if a mastoidectomy has been performed.

Endaural approach

The endaural technique is useful with many perforations, especially when a small atticotomy is anticipated (when improved access to and visualization of the epitympanum is needed). Many of the steps involved in the transcanal technique are similarly performed in the endaural tympanoplasty as well. When performing an endaural medial tympanoplasty procedure, the following steps are followed:

1. The canal is prepared as detailed above, but the injection may continue laterally to the lateral external auditory canal and tragus.
2. An incision is made at 12 o’clock and extended superolaterally between the tragus and helical root.
3. A medially-based tympanomeatal flap is raised, and the middle ear is entered with the same care as described previously. The tympanic membrane is freed superiorly and inferiorly.
4. Middle ear work is carried out as indicated. Atticotomy can be performed using a small curette or drill if access into the epitympanum is needed.
5. Grafting is performed and the tympanomeatal flap is laid back down. Gelfoam is placed along the tympanic membrane and fills the canal. Antibiotic ointment and a cotton ball are used laterally.

Postauricular approach

The postauricular technique is the most commonly performed approach for either revision tympanoplasties or those in which a mastoidectomy is anticipated. This technique offers the best visualization of the anterior tympanic membrane and is preferred for large anterior perforations. In addition, it can be combined with mastoidectomy if disease is found in the mastoid that requires the surgeon’s attention. A basic outline of the procedure follows:

1. The canal is prepared in a similar fashion to the transcanal technique.
2. Radial and horizontal canal incisions are made as described previously, and the canal is packed with cotton soaked in oxymetazoline or epinephrine.
3. A postauricular incision is marked 5 mm posterior to the auricular crease in a curvilinear fashion, extending form the mastoid tip to the temporal line. The incision is injected with 1% lidocaine with either 1:100,000 epinephrine or 0.5% lidocaine with 1:200,000 epinephrine. The incision is carried down through the skin and subcutaneous tissue with care not to enter the ear canal. When the temporalis fascia is reached, a graft can be harvested using a Freer elevator and scissors. If multiple previous grafts have been harvested, either tissue from the contralateral ear or AlloDerm can be used as well.
4. A periosteal incision is made in a “T” or “7” fashion, and the periosteum is raised into the lateral ear canal until the previously-made canal incisions are reached. The cotton in the ear canal is removed.
5. A rubber Penrose drain can be inserted to retract the lateral canal and auricle anteriorly. Self-retaining retractors such as Weitlaner or Perkins retractors are used to provide further exposure. The perforation is visualized and prepared.
6. The tympanomeatal flap is raised medially and the middle ear is entered as described previously. Do not suction on the flap.
7. Canalplasty can be performed and middle ear work is carried out as indicated, including ossicular reconstruction. The perforation is grafted, and the tympanomeatal flap is laid back down with Gelfoam layered lateral to the tympanic membrane.
8. The auricle and lateral ear canal are relaxed and the postauricular incision is closed in a layered fashion. The remainder of the ear canal is packed with Gelfoam and antibiotic ointment. A pressure dressing is applied to prevent a postauricular hematoma.

Grafting technique

Although variations exist, 2 primary grafting techniques exist: medial grafting (or underlay) and lateral grafting (or overlay). These terms refer to the position of the graft in relation to the fibrous annulus, not to the malleus or tympanic remnant.

The medial grafting technique is performed as described previously. The primary advantage of the medial graft technique is that it is quicker and easier to perform than lateral grafting. It also carries a high success rate (approximately 90% in experienced hands). The biggest disadvantage is its limited exposure and poor utility for larger perforations and its difficulty with repair of near-total perforations.

Advantages of the lateral graft technique include wide exposure and versatility for larger perforations and for any needed ossicular reconstruction. Disadvantages include the requirement of a higher technical skill level, a longer operative time, slower healing rate, and the risk of blunting and lateralization of the graft. The lateral graft technique is championed by the some doctors as a technique more suited for total drum replacement. The basic steps involved in lateral grafting are described as follows:

1. Lateral (overlay) tympanoplasty is performed through the previously-described postauricular incision. Important differences exist in the canal incisions. In this procedure, a vascular strip is created by making radial incisions at about 2 o’clock and 5 o’clock. These incisions are connected medially just lateral to the annulus on the posterior canal wall and laterally just medial to the bony-cartilaginous junction along the anterior canal wall.
2. The skin of the anterior external auditory canal is raised medially. When the annulus is reached, squamous epithelium is raised off of the tympanic remnant, and the canal skin is removed in continuity with the remnant skin and stored in saline solution. This maneuver is done with a cupped forceps.
3. Bony canalplasty can be performed anteriorly to ensure visualization of the entire annulus. Protecting the flap with a portion of trimmed Silastic as a shield is helpful. Care must be taken not to enter the glenoid fossa, which risks injuring the temporomandibular joint (TMJ) and causing prolapse into the ear canal.
4. Antibiotic-soaked Gelfoam is packed into the middle ear to support the tympanic remnant. The fascia graft is placed medial to the malleus and draped onto the posterior canal wall for stabilization. If possible, the graft should not extend onto the anterior canal wall in an effort to prevent blunting of the graft.
5. The canal skin/tympanic remnant is returned and placed lateral to the graft and carefully positioned. Gelfoam is then packed tightly into the anterior aspect of the medial canal to prevent blunting, and the vascular strip is laid back down, covering the lateral extension of the fascia graft to improve its blood supply. Antibiotic-soaked Gelfoam is then packed into the rest of the external auditory canal.
6. The postauricular incision is closed in layers, and antibiotic ointment is placed on the incision and in the lateral canal. A cotton ball is placed in the external auditory meatus, and a mastoid pressure dressing is applied.

Myringoplasty recovery

After the operation, your child’s surgical team will take your child to the recovery room, also called the Post Anesthetic Care Unit (PACU). This is where your child will wake up. Your child will stay in PACU for about one hour. Your child’s surgical team will then move your child to a room on the nursing unit.

Your child’s surgical team will give your child fluids through a tube in their arm, called an IV, until they are able to drink easily. Your child will have a gauze bandage around their head, which will be taken off the day after the operation.

Postoperative hearing should be immediately assessed in the recovery room with a tuning fork. If a pressure dressing is applied, it should be removed on the first or second postoperative day depending on surgeon preference.

Although the ear must be kept otherwise dry, patients are allowed to wash their hair, while keeping a cotton ball with Vaseline in the canal for dry ear measures. Pain is usually managed with acetaminophen and/or ibuprofen. Narcotics such as hydrocodone (Vicodin or Norco) are usually prescribed when a post-auricular approach is used. Oral antibiotics are the surgeon’s preference and can be given for 5-7 days. A cotton ball is replaced in the external auditory meatus as needed for bleeding or drainage. Ototopical drops are typically administered postoperatively for 7-21 days after surgery and continued until the first postoperative visit.

At the first postoperative visit (3-4 weeks after surgery), the ear is examined under the microscope, and any canal packing or residual antibiotic is removed. At this time, a good assessment can be made as to the healing and neovascularization of the graft. Granulation tissue at the tympanomeatal flap is addressed. Ototopical drops are continued as the graft continues to heal. Postoperative audiometric testing is delayed until healing is complete (typically 6-12 weeks). Follow-up visits are scheduled to ensure complete proper healing and restoration of hearing.

Medications that may be prescribed after surgery

• Pain control: Acetaminophen (Tylenol) liquid solution may be given. Some children will requireprescription pain medication. Pain may be worse during evening; some children should be given medication at night.
• NO ibuprofen (Motrin or Advil) or aspirin for twoweeks after surgeryunless otherwiseinstructed by physician.
• Antibiotic eardrops may be prescribed twoweeks after surgery. Give drops at room temperature.
• Antibiotics may be prescribed for 7 to 10 days.

Special precautions after ear surgery

1. No nose blowing for two weeks. Sneeze with an open mouth.
2. Water precautions: Keep ear canal dry for the first twoweeks;place cotton ball coated with Vaseline in the ear(s) when bathing. Hair may be washed twodays after surgery. The sutures may get wet but the ear canal should stay dry. No swimming for usually 4 to 6 weeks. The physician will advise you when the ear can get wet.
3. Wound and suture line care: A large dressing is usually applied after surgery and should be left in place for one-twodays. After the dressing is removed (at your appointment or at home as instructed by your doctor), clean the incisionwith hydrogen peroxide and apply bacitracin ointment. Use Q-tips or cotton balls to clean the incision. Wash your hands before and after cleaning the incision. Apply a cotton ball to the outside of the ear canal if drainage is present.
4. Keep the incision protected from the sun for 6 to 12 months, keep covered or apply sunscreen.

Taking care of your child at home

Please follow these steps at home to help your child get better:

• Your child may have a small gauze bandage over their ear. Please keep this bandage on for one or two days after going home.
• Do not let the cut behind your child’s ear get wet. Do not get any water in the ear. Your child can have a bath, but take care not to pull on the ear or get it wet if you need to wash their hair.
• Do not let your child play contact sports like hockey or soccer until the ENT doctor says it is OK.
• Do not let your child go swimming until the ENT doctor says it is OK.
• Do not let your child play a musical instrument that you blow in until the ENT doctor says it is OK.
• Do not let your child blow their nose. Have them cough or sneeze with their mouth open.
• Your child may return to school or day care when your ENT doctor says it is OK. Usually, this will be one week after the operation.

Pain management at home

Follow these instructions when your child goes home after the procedure.

You may give your child medicine for pain.

You may receive a prescription for pain medication before you leave the hospital. Follow the dosage instructions given to you by the pharmacist. Although these prescription pain medications can be beneficial, they are also potentially very dangerous if not used properly.

When using these medications, if you notice any changes in either breathing or level of drowsiness that concern you, stop the medication and seek medical attention. If your child is unresponsive, call your local emergency services number immediately.

Do not give your child over-the-counter medicine that may have a sedative effect (makes people sleepy) while giving the prescription for pain medicine. Examples of these medicines are decongestants and antihistamines. Discuss these medications with your pharmacist.

You may give your child acetaminophen if they have pain. Give the dose printed on the bottle for your child’s age. Do not give your child ibuprofen or acetylsalicylic acid for two weeks after the surgery. These medications could increase your child’s risk of bleeding after the operation. Check with the nurse or doctor first before giving these medicines to your child.

Myringoplasty recovery time

Routine activities may be resumed in 2-5 days. Most children return to school in 3 to 5 days if eating and sleeping well and pain-free. Vigorous exercise, heavy lifting and physical activities should be avoided for 2 weeks. No swimming until advised by your doctor, typically in 4-6 weeks.

Follow-up care

A follow-up appointment with the ENT doctor

The ENT unit will make a follow-up appointment with the doctor for your child. If everything is normal during the appointment, the doctor will:

• Check your child’s ear to see how it is healing.
• Take out the packing from your child’s ear.
• Tell you when your child can start to play sports again.

Myringoplasty complications

Common complaints after surgery:

• Nausea and vomiting may occur for the first 24 to 48 hours.
• Pain: Mild to moderate ear pain and/or pain at theincision site for 3 to 5 daysis expected.
• Fever: A low-grade fever may be observed several days.
• Ear drainage after surgery. Packing material is placed in the ear canal; sometimes there is clear, pink, or bloody drainage from the ear for 3-5 days. This may also occurwhen ear drops are started.
• Dizziness or unsteadiness: Dizziness is common for several days.
• Decreased hearing in the operated ear for several weeks.

Complications of the surgery include recurrence of the perforation, tympanic membrane retraction, otorrhea, cholesteatoma development, persistence or worsening of any conductive hearing loss, sensorineural hearing loss (rare), and taste disturbances. Post-auricular incisions are at risk for hematoma, and a mastoid pressure dressing is recommended for the first postoperative night. Outcomes can be optimized by a proper and detailed preoperative assessment and the careful construction of an effective surgical plan.

The graft can fail because of infection, failure to pack the graft securely in place, technical error, failure to clear mastoid and middle ear disease, and because of a concurrent undetected cholesteatoma. Excising all tympanosclerosis at the edge of the perforation so as to allow vascularized perimeters to incorporate the graft is critical.

Myringoplasty outcomes

The indications and outcomes vary depending on the specific clinical problem. Success rates of tympanic membrane closure vary greatly in the literature (35-98%) but are usually greater than 80% and depend largely on the size and location of the perforation, surgical technique, and overall health of the middle ear ⁸.

1. Aggarwal R, Saeed SR, Green KJ. Myringoplasty. J Laryngol Otol. 2006 Jun. 120(6):429-32.[↩]
2. Webb B, Chang CYJ. Efficacy of Tympanoplasty without mastoidectomy for Chronic Superative Otitis Media. Arch of Otolaryngol Head and Neck Surg. 2008/11. 1155-1158.[↩]
3. Chang CYJ. Chronic Disorders of the Middle Ear and Mastoid (Tympanic Membrane Perforations and Cholesteatoma. Mitchell RB. Pediatric Otolaryngology for the Clinician. New York, NY: Springer; 2009.[↩]
4. Wright D, Safranek S. Treatment of otitis media with perforated tympanic membrane. Am Fam Physician. 2009 Apr 15. 79(8):650, 654.[↩]
5. Luetje III CM. Reconstruction of the Tympanic Membrane and Ossicular Chain. Bailey BJ. Head & Neck Surgery – Otolaryngology. 4th Edition. Philadelphia, PA: Lippincott Williams & Wilkins; 2006.[↩]
6. Wasson JD, Papadimitriou CE, Pau H. Myringoplasty: impact of perforation size on closure and audiological improvement. J Laryngol Otol. 2009 Sep. 123(9):973-7.[↩]
7. Dornhoffer JL. Cartilage tympanoplasty. Otolaryngol Clin North Am. 2006 Dec. 39(6):1161-76.[↩]
8. Hardman J, Muzaffar J, Nankivell P, Coulson C. Tympanoplasty for Chronic Tympanic Membrane Perforation in Children: Systematic Review and Meta-analysis. Otol Neurotol. 2015 Jun. 36 (5):796-804.[↩]

Protruding ears

Protruding ears also called prominent ears, are ears that stick out more than 2 cm from the side of the head. Protruding ears don’t cause any functional problems such as hearing loss.

In most people, protruding or prominent ears are caused by an underdeveloped antihelical fold. When the antihelical fold does not form correctly, it causes the helix (the outer rim of the ear) to stick out.

Most people with protruding ears also have a deep concha, the bowl-shaped space just outside the opening of the ear canal, which pushes the entire ear away from the side of the head.

Figure 1. Ear anatomy

Normal external ear anatomy

The ear is shaped like the letter C, formed by the helix and the earlobe. Inside the C is the letter Y, formed by the antihelix and the superior and inferior crura. The central part of the ear is shaped like a conch sea shell, and is called the concha. There is a small bump in front of the ear canal called the tragus. On the other side of the concha is another bump called the antitragus.

The ear is made primarily of cartilage covered by skin. The earlobe has no cartilage and is made of skin and fat. Although there are some muscles attached to the ear, most people cannot control them, which is why only a small percentage of people can wiggle their ears. The external ear is supplied by four different sensory nerves.

Protruding ears treatment

There are both non-surgical and surgical options for treating protruding ears.

Non-surgical ear molding

If a protruding ear is discovered in the first few weeks after birth, ear molding may correct this deformity and avoid the need for surgery. Ear molding works best in the first few weeks of life when infant ears are soft and pliable. Infant ears have very high levels of maternal estrogen (estrogen which crossed from mother to baby while in the womb and during the birthing process). Because of the increased estrogen levels, infant ears are very moldable, soft and responsive to external molding during the first few weeks and months after birth.

By 6 weeks of age, these levels of maternal estrogen fall to normal, and the ears become more rigid and less pliable. This is why early intervention is so important. If neonatal ear deformities are recognized early enough, they can often be successfully treated by non-surgical molding, preventing the need for surgery later in life.

Because some ear deformities will self-correct over time, your child should be monitored closely for the first 7 to 10 days of life. If the shape or deformity of the ear doesn’t improve in the first week or two, non-surgical infant ear molding may be recommended as the most appropriate treatment approach.

Ear molding uses a combination of commercially available ear molding devices and orthodontic molding materials to reshape the ear.

First, your child will be fit with a non-surgical molding appliance. For the best results, the device should be applied within the first one to two weeks of life. The device is worn continuously for two weeks.

After two weeks, your child’s doctor will examine your child’s ear. If the deformity has not been corrected yet, a new device will be reapplied. This process is repeated every two weeks until acceptable improvement or correction is seen.

Most ears, if treated early, respond to ear molding to improve the shape of the ear. In general, the younger your child is when treatment for prominent ears is started, the shorter the duration of therapy. However, children a few months of age have been treated successfully with non-surgical ear molding.

Protruding ears surgery

Surgery to correct protruding ears is called a setback otoplasty. It can be performed as early as 5 to 6 years of age when ears are almost fully grown.

The procedure to correct protruding ears is usually performed through an incision behind the ears. The cartilage is reshaped to create an antihelical fold. This will support the ear in its new position closer to the head. Sometimes, additional sutures are placed on the back of the conchal to bring the entire ear closer to the side of the head. A postoperative dressing is used to help keep the ears in their new positions. This dressing will typically stay in place for 1 to 2 weeks. Although a general anesthetic is needed, the operation is done on an outpatient basis and your child will be able to return home the same day.

Insurance companies often consider otoplasty to be a cosmetic operation, and therefore they may not cover the cost of this procedure. Before cosmetic ear surgery, discuss the procedure with your insurance carrier to determine what coverage, if any, you can expect.

Ear plastic surgery

To correct prominent ears that lack folds, an ENT (ear, nose, and throat) specialist, or otolaryngologist, places permanent stitches in the upper ear cartilage and ties them in a way that creates a fold to prop up the ear. Scar tissue will form later, holding the fold in place. Corrective surgery, called otoplasty, may be considered on ears that stick out more than 4/5ths of an inch (2 cm) from the back of the head. It can be performed at any age after the ears have reached full size, usually at five- or six-years-old. Having the surgery at a young age has two benefits: (1) the cartilage is more pliable, making it easier to reshape, and (2) the child will experience the psychological benefits of the cosmetic improvement.

An ENT specialist begins the surgery with an incision behind the ear where the ear joins the head. In addition, ears may also be reshaped, reduced in size, or made more symmetrical. The reshaped ear is then secured in position while healing occurs. Typically, otoplasty surgery takes about two hours. The soft dressings over the ears will be used for a few weeks as protection, and the patient usually experiences only mild discomfort. Headbands are sometimes recommended beyond that for a month following surgery.

Childhood glaucoma

Childhood glaucoma also known as congenital glaucoma, pediatric glaucoma, infantile glaucoma is a rare childhood eye condition where high pressure builds up inside the eye during fetal development that is either present at birth or develops during very early childhood, potentially causing vision loss and even blindness if left untreated ¹, ², ³, ⁴, ⁵, ⁶, ⁷. Glaucoma can affect one eye or both. Children with childhood glaucoma have ocular hypertension (high pressure inside their eyes). The fluids in their eyes (aqueous humor) fail to drain normally, so they build up, raising the pressure inside. This puts stress on their optic nerves and can eventually cause structural changes to their eyes. Childhood glaucoma is typically diagnosed within the first few months of life commonly in children under 2 years of age caused by a developmental defect in the eye’s drainage system, preventing fluid from flowing out properly and is  often suspected when there is eye enlargement at birth ⁴. Congenital glaucoma affects about 1 in 10,000 children under 2 years of age in the United States ⁸, ⁹.

Eye doctors often classify childhood glaucoma by the age when it first appears ⁶:

1. Newborn (neonatal) onset (0-1 month)
2. Infantile onset (>1-24 months)
3. Late onset or late-recognized (>24 months)
4. Spontaneously arrested primary congenital glaucoma (very rare), classic findings of eye stretching including Haab striae with normal intraocular pressure (IOP); must follow as glaucoma suspects.

Primary congenital glaucoma commonly presents between the ages of 3-9 months, but the most severe form is the newborn onset ⁶. Infantile glaucoma affects individuals between the ages of 1 and 36 months ¹⁰, while juvenile glaucoma is used to indicate individuals diagnosed with glaucoma between the ages of 3 and 40 years ¹¹. In most cases, childhood glaucoma is diagnosed by the age of six months, with 80% diagnosed in the first year of life.

The elevated intraocular pressure (IOP) is associated with the classic “triad” of symptoms such as eyes are sensitive to light (photophobia), excessive tearing of the eye (epiphora) and uncontrollable muscle twitching that forces eyes closed (blepharospasm), which occurs due to rapid expansion of the child’s eye causing buphthalmos (“ox-eyed” in Greek), corneal enlargement, horizontal or oblique breaks in Descemet membrane (Haab striae) and subsequent corneal edema and opacification (see Figure 3 and 4 below). If Haab striae and buphthalmos are seen without elevated intraocular pressure (IOP), optic nerve cupping or corneal edema, then the patient has spontaneously arrested primary congenital glaucoma ². It’s very important to recognize and treat childhood glaucoma as soon as possible to minimize the damage and vision loss it can cause in your child.

Due to the elasticity of the eye in young children, the 2013 International Classification System for Childhood Glaucoma defined childhood glaucoma as irreversible or reversible damage to the whole eye and not just the optic nerve as glaucoma is defined for adults ². Therefore, additional important clinical signs in primary congenital glaucoma, besides elevated intraocular pressure (IOP) and optic nerve cupping, are corneal enlargement and clouding, Haab striae, and buphthalmos. Not all signs are always present, however, and other parts of the eye also stretch with elevated intraocular pressure (IOP). Diagnosis of childhood glaucoma can be delayed if corneas remain clear, despite being enlarged, and bilateral primary congenital glaucoma can be missed if signs and symptoms are mild in one eye. Irreversible vision loss results if elevated intraocular pressure (IOP) is untreated or uncontrolled in primary congenital glaucoma. Optic nerve damage occurs, and focal corneal edema overlying Haab striae, which can be single or multiple, can lead to permanent corneal scarring and opacification. This corneal scarring can obscure the visual axis or cause astigmatism (a common eye condition where the cornea or sometimes the lens doesn’t have a perfectly round spherical shape leading to blurry or distorted vision at all distances, this irregular shape causes light rays to focus at multiple points on the retina instead of a single point, resulting in a fuzzy or wavy image) with or without refractive amblyopia. Amblyopia may also develop due to optic nerve damage, anisometropia (a condition of asymmetric refraction between the two eyes), strabismus or a combination.

There are many causes of childhood glaucoma. It can be hereditary or it can be associated with other eye disorders.

• If childhood glaucoma cannot be attributed to any other cause, other noticeable eye defects or systemic problem, it is classified as primary congenital glaucoma. The cause of primary congenital glaucoma is not completely understood, though there is significant research to suggest that the trabecular meshwork is immature and compressed. Studies suggest that the normal posterior migration of embryonic neural crest cells destined to become the trabecular meshwork is abnormally halted ¹². The drainage angle where the inside of the sclera (the white of your eye) and the outer edge of your iris meet of children with primary congenital glaucoma is described as immature, thick, and compressed. High intraocular pressures (IOP) are believed to be a consequence of increased resistance to aqueous outflow in this abnormal trabecular meshwork. Researchers have identified several gene mutations that can lead to primary congenital glaucoma. Mutations in the CYP1B1 (cytochrome P450 family 1 subfamily B member 1) gene are the predominant genetic anomalies linked to primary congenital glaucoma ¹³.
• If childhood glaucoma is a result of another eye disorder, eye injury, or other disease, it is classified as secondary childhood glaucoma.
  • Associated with eye abnormalities e.g., Axenfeld-Rieger syndrome, aniridia (a rare genetic eye disorder characterized by the complete or partial absence of the iris, the colored part of the eye), iridotrabecular dysgenesis, Peter’s anomaly, sclerocornea (a rare, non-progressive, congenital condition where the cornea, normally transparent, becomes opaque and blends with the sclera, the white part of the eye), microcornea (a congenital condition where the cornea, the transparent front part of the eye, is smaller than normal, with a horizontal diameter of less than 10-11 mm), microphthalmos (a developmental disorder of the eye where one or both eyes are abnormally small and have anatomical malformations), ectopia lentis, persistent fetal vasculature, oculodermal melanocytosis, posterior polymorphous dystrophy,
  • Associated with systemic abnormalities e.g., chromosomal disorders like trisomy 21 (Down syndrome), connective tissue disorders such as Marfan syndrome, Stickler syndrome (a group of genetic disorders that primarily affect connective tissues, particularly in the face, eyes, ears, and joints), phakomatoses (a group of genetic disorders also known as neurocutaneous syndromes or neuro-oculo-cutaneous syndromes characterized by systemic hamartomas, primarily affecting the central nervous system, eyes, and skin) common examples include neurofibromatosis (types 1 and 2), Sturge-Weber syndrome, tuberous sclerosis, Lowe syndrome and von Hippel-Lindau disease
  • Glaucoma secondary to acquired causes e.g., retinopathy of prematurity, eye trauma, intraocular tumors, uveitis, eye inflammation, lens‑induced (with/without pupillary block), steroid-induced, intraocular infections, maternal rubella (congenital rubella syndrome), raised episcleral venous pressure
  • Glaucoma after surgery for congenital cataract.

Childhood glaucoma commonly starts with a defect in the way your child’s eye develops. The most common defect is in the trabecular meshwork, the tissue that the eye fluids (aqueous humor) drain through. When the trabecular meshwork doesn’t develop right, the aqueous humor fluids don’t drain properly. The buildup of fluids (aqueous humor) causes pressure in your child’s eye, which damages their optic nerve. It can also cause their cornea to enlarge, stretch, tear and scar. This process is progressive. How fast it progresses depends on how severe the defect in your child’s eye is, how much fluid (aqueous humor) is building up and how high the pressure is inside the eye (intraocular pressure [IOP]). When glaucoma appears in young infants, it’s because these conditions were already progressing during fetal development. When symptoms appear later, it’s because these conditions were less severe at birth, so they took longer to build up.

To diagnose childhood glaucoma, your child’s eye doctor will ask about your child’s medical history and do a complete eye examination of your child.

Furthermore, your child’s eye doctor may perform diagnostic procedures such as:

• Visual acuity test – the common eye chart test (with letters and images), which measures vision ability at various distances.
• Pupil dilation – the pupil is widened with eyedrops to allow a close-up examination of the eye’s retina and optic nerve.
• Visual field – a test to measure a child’s side (peripheral) vision. Lost peripheral vision may be an indication of glaucoma.
• Tonometry – a standard test to determine the fluid pressure inside the eye.

Younger children may be examined with hand-held instruments, whereas older children are often examined with standard equipment that is used with adults. An eye examination can be difficult for a child. It is important that parents encourage cooperation. At times, the child may have to be examined under anesthesia, especially young children, in order to examine the eye and the fluid drainage system, and to determine the appropriate treatment.

Specific treatment for glaucoma will be determined by your child’s eye doctor based on:

• your child’s age, overall health, and medical history
• extent of the disease
• your child’s tolerance for specific medications, procedures, or therapies
• expectations for the course of the disease
• your opinion or preference

It is important for treatment of childhood glaucoma to start as early as possible. Treatment may include:

• Medications. Some medications cause the eye to produce less fluid, while others lower pressure by helping fluid drain from the eye.
• Surgery. The purpose of surgery is to create a new opening for fluid to leave the eye. Surgical procedures are performed by using microsurgery or lasers.

Both medications and surgery have been successfully used to treat childhood glaucoma. However, surgery is the primary treatment modality for primary congenital glaucoma. In managing secondary childhood glaucoma, medications is the first-line treatment ¹⁴.

Surgical procedures used to treat glaucoma in children include the following:

• Trabeculotomy and goniotomy.
  • Trabeculotomy is a surgical procedure, primarily used in the treatment of childhood glaucoma, that creates a new drainage opening in the eye’s trabecular meshwork, improving the outflow of aqueous humor and reducing the intraocular pressure (IOP).
  • Goniotomy is a microinvasive glaucoma surgery (MIGS) technique that improves fluid flow in the eye to lower intraocular pressure (IOP). A goniotomy involves making a small incision within the trabecular meshwork, the eye’s natural drainage system, to create a more efficient pathway for fluid outflow. This procedure can be used to treat conditions like childhood glaucoma.
• Trabeculectomy. Trabeculectomy is a surgical procedure that involves the removal of part of the trabecular meshwork drainage system, allowing the fluid to drain from the eye. Trabeculectomy works by creating a new drainage pathway for the fluid (aqueous humor) within the eye, allowing it to drain into a space beneath the outer layer of the eye (conjunctiva). This new pathway, called a bleb, helps reduce eye pressure and can slow or prevent further vision loss.
• Iridotomy. Iridotomy is a surgical procedure to treat or prevent angle-closure glaucoma, a condition where the iris (colored part of the eye) blocks the drainage angle, leading to increased eye pressure. The eye surgeon may use a laser to create this hole. Laser iridotomy involves using a laser to create a small hole in the iris, allowing fluid to flow freely and preventing or relieving pressure build-up.
• Cyclophotocoagulation. Cyclophotocoagulation is a laser procedure that uses a laser beam to freeze selected areas of the ciliary body – the part of the eye that produces aqueous humor – to reduce the production of fluid and reduce intraocular pressure (IOP). Cyclophotocoagulation is a type of cyclodestruction procedure, meaning it aims to reduce intraocular pressure (IOP) by damaging the ciliary body, a key part of the eye that produces aqueous humor. This type of surgery may be performed with severe cases of childhood glaucoma.

The primary treatment of primary congenital glaucoma is angle surgery, either goniotomy or trabeculotomy, to lower intraocular pressure (IOP) by improving aqueous outflow. If angle surgery is not successful, trabeculectomy enhanced with mitomycin C or glaucoma implant surgery with a Molteno, Baerveldt, or Ahmed implant can be performed. In refractory cases, cycloablation can be performed using an Nd:YAG laser, diode laser, or cryotherapy, with diode laser being the most widely used device. Medications, either topically or orally, is typically used as a temporizing measure prior to surgery and to help decrease corneal clouding to facilitate goniotomy, and to supplement intraocular pressure (IOP) control after surgery.

Figure 1. Eye anatomy

Figure 2. Congenital glaucoma

Footnote: Primary congenital glaucoma with cloudy corneas.

Figure 3. Buphthalmos in primary congenital glaucoma

Footnotes: Buphthalmos is derived from “ox-eyed” in Greek. Buphthalmos describes the visible enlargement of the eyeball at birth or soon after due to increased intraocular pressure (IOP) ¹⁵. Buphthalmic eyes typically have corneal diameters exceeding 12 mm in newborns or 13 mm in children older than 1 year ¹⁵. The corneal diameters sometimes exceed 16 mm, with the globe appearing noticeably enlarged. Normal corneal diameters are 9.5 to 10.5 mm at birth and 11 to 12 mm by age 1 ¹⁶. Primary congenital glaucoma (onset at birth) and primary infantile glaucoma (onset after birth to 3 years) are the most frequent causes of buphthalmos ¹⁷, ¹⁸. Corneal edema, increased corneal diameter, and optic disc cupping are the classical manifestations in patients with buphthalmos ¹⁹.

Figure 4. Haab striae in primary congenital glaucoma

Footnotes: Haab striae are curvilinear breaks in Descemet’s membrane, resulting acutely from stretching of the cornea in primary congenital glaucoma. Haab striae are typically oriented horizontally or concentric to the limbus in contrast to Descemet’s tears, resulting from birth trauma, that are usually vertical or obliquely oriented.

How would a parent know if a child is suffering from glaucoma?

In keeping with the rest of an infant the immature eye is floppy and somewhat elastic. Thus early in life (that is before the second birthday) raised intraocular pressure (IOP) will stretch the eye and actually cause it to increase in size that is the eyeball expands in all directions rather like a balloon being inflated. Early medical writers termed this buphthalmos (ox eye) as this increase in size of the eye was thought to make the infant’s eye look like an ox’s eye.

The stretching of the eye has a number of harmful effects on the eye. As the eye enlarges the cornea increases in size. One of the many layers of the cornea called the Descemet’s membrane does not have much give and rather than stretch it will split as the eye enlarges leading to “striae”, which are areas of bare stroma bordered by two separated edges of Descemet’s membrane that become ridges due to deposition of hyaline ²². These are called Haab striae (see Figure 4) and are associated with acute overlying focal corneal edema when the intraocular pressure (IOP) is high. Haab striae occur in about 25% of primary congenital glaucoma eyes presenting at birth, and more than 60% of primary congenital glaucoma eyes identified at 6 months of age ²³. There may be single or multiple, and are oriented horizontally or obliquely. In addition, the Descemet’s membrane splitting results in the cornea losing some of its clarity and becoming cloudy. This cloudiness of the cornea is the result of fluid entering the cornea from the anterior chamber via the splits in Descemet’s membrane because the endothelial cell layer cannot pump fluid out of the cornea in an eye with elevated intraocular pressure (IOP). This cloudiness of the cornea is known as corneal edema. Corneal edema causes discomfort and sensitivity to light and increased tear production.

After normalization of intraocular pressure (IOP), corneal edema may clear; however, Haab striae remain and may be associated with corneal scarring. In poorly controlled cases of primary congenital glaucoma may end up with dense stromal opacification even after intraocular pressure (IOP) is controlled.

Therefore, the main features of childhood glaucoma that may be identified by a parent are photophobia (sensitivity to light), increased tearing with an enlarged and cloudy cornea.

What happens when glaucoma is suspected in a young child?

The child needs to be assessed by an ophthalmologist (eye specialist). Ideally the child should be referred to an ophthalmologist with experience in managing childhood glaucoma. Often an examination under anesthetic is required to adequately examine the child and confirm the diagnosis of glaucoma. The diagnosis is confirmed by the presence of typical corneal changes (enlargement, clouding and splits in Descemet’s membrane called Haab striae), raised intraocular pressure (IOP) and optic disc cupping.

Will my child’s vision be impaired?

Severe loss of vision due to infantile glaucoma is fortunately rare. However, if glaucoma is not appropriately treated there is a risk of progressive visual impairment. Rarely does childhood glaucoma result in severe visual impairment but life-long follow-up is needed for all children after a diagnosis of glaucoma is made. Vision impairment is particularly seen if the onset of the glaucoma is at or before birth. Glasses are commonly required for myopia (short sightedness). This is due to the overall length of the eyeball being increased by the raised intraocular pressure. Photophobia (sensitivity to light) may be a persistent problem if the splits in Descemet’s membrane are severe.

Therefore prompt recognition and timely treatment will improve the chance of a good vision outcome.

Will my child’s lifestyle need to alter in any way?

Most children with childhood glaucoma lead normal lives. Glasses may be required for focusing errors or photophobia (sensitivity to light). Adolescents often have difficulty accepting the need for long-term medication and regular medical review. Ensuring compliance with regular use of eye drops may be especially difficult. The small number of children with more severe visual impairment will require some degree of help at school.

Is childhood glaucoma hereditary?

Some types of childhood glaucoma are hereditary. About 10% of primary congenital glaucoma or infantile glaucoma cases are inherited. Recent research has identified some specific gene mutations linked to this disease; for which genetic testing and counseling for affected families is may be available.

Other conditions that cause secondary glaucoma can be inherited. For example, neurofibromatosis and aniridia are dominantly inherited and are passed on to the children of affected individuals approximately 50% of the time. The incidence of glaucoma that occurs in association with these conditions, however, is less predictable.

What are the chances of another baby of mine developing glaucoma?

The risk is not zero but it is quite low. Primary open angle glaucoma in adolescents may show a familial tendency just as in adult open angle glaucoma. Inherited juvenile open angle glaucoma is well recognized but very rare. This form of glaucoma is generally not detectable till the twenties rather than during later childhood.

Aqueous Humor Production and Physiology

The aqueous humor is a water-like fluid that is produced by the ciliary body epithelium that sits directly behind the iris (the colored part of your eye). Aqueous humor is produced at a rate of 2-3 microliters per minute (2-3 μL/minute) ²⁴, ²⁵. The aqueous humor is composed of organic and inorganic ions, carbon dioxide, amino acids, carbohydrates, glutathione, and water ²⁴, ²⁶. The aqueous humor fills the anterior chamber of your eye with continual production, secretion, and reabsorption ²⁴. The production, circulation and reabsorption of aqueous humor are vital processes maintaining homeostasis of the eye. Imbalances between the production and secretion of aqueous humor may lead to increased intraocular pressure (IOP) and optic nerve damage such as in the setting of ocular hypertension or glaucoma.

Aqueous humor functions as a physical component allowing clear optics and filling the anterior chamber of the eye ²⁴, ²⁵. The aqueous humor is responsible for providing nourishment to the avascular components of the anterior chamber including the cornea and lens ²⁴, ²⁵. In addition, aqueous humor is responsible for removing waste products, blood, macrophages and other debris from the anterior chamber, including the trabecular meshwork ²⁴, ²⁵. The structure and function of the trabecular meshwork may become compromised by chronic oxidative stress from reactive oxygen species and insufficient antioxidant defense in the aqueous humor ²⁴, ²⁵, ²⁷, ²⁸. Decreased levels of antioxidants in aqueous humor are present in glaucomatous eyes versus normal eyes, consistent with the presence of increased oxidative stress and low-grade inflammation ²⁷, ²⁸.

The primary anatomic structures vital to the homeostasis of aqueous humor include the ciliary body as the site of principle production, and the trabecular meshwork and uveoscleral pathway as the sites of primary outflow ²⁴, ²⁹. Aqueous humor is produced by the ciliary body via a multistep process closely correlating with systemic vascular blood flow ²⁴, ³⁰, ³¹. Initially, blood enters the ciliary processes, which propels ultrafiltrate from the blood into the ciliary interstitial space via a pressure gradient ²⁴, ³⁰, ³¹. Next, the ciliary epithelium transports plasma components from the basal to the apical surface in order to synthesize aqueous humor and transport it into the posterior chamber ²⁴, ³⁰, ³¹. Passive diffusion and ultrafiltration are key in initial synthesis, and active secretion across a blood-aqueous barrier via aquaporins, Na-K-ATPase and carbonic anhydrase enzymes are necessary for final synthesis ²⁴, ³⁰, ³¹, ³². These active transport enzymes necessary for final synthesis are common pharmacologic targets in decreasing aqueous humor production. Although systemic blood flow via the ciliary artery is required for the initial production of ultrafiltrate, the production of aqueous humor is independent from systemic blood pressure due to a fixed rate of 4% filtration of plasma ³¹. Therefore, there is minimal association between systemic high blood pressure (hypertension) and elevated intraocular pressure (IOP). The estimated rate of aqueous humor production is approximately 2.4 microliters per minute (2.4 μL/minute), with diurnal variations leading to higher aqueous humor flow in the morning and lower flow in the evening ²⁴, ³⁰.

While aqueous humor production is well documented, the mechanism of drainage is still poorly understood.

There are 2 main drainage pathways for aqueous humor ²⁴, ³³, ³⁰:

1. The conventional pathway via trabecular meshwork, Schlemm’s canal, collector channels, and the episcleral venous system), and
2. The unconventional pathway via uveoscleral, uveovortex, uveolymphatic.

The conventional pathway drainage pathways for aqueous humor involves passive drainage throughout the trabecular meshwork although the Schlemm’s canal has been documented with paracellular and intracellular pores ²⁴, ³³, ³⁰. The trabecular meshwork is a triangular porous structure composed of a layer of connective tissue and endothelium with sympathetic innervation from superior sympathetic ganglion, and parasympathetic innervation from the ciliary ganglion ²⁴, ³³, ³⁰. The trabecular meshwork may be divided into the uveal meshwork (iris root, ciliary body, peripheral cornea), corneoscleral meshwork (scleral spur), and juxtacanalicular meshwork (transition into Schlemm’s canal) ²⁴, ³³, ³⁰. Schlemm’s canal is a structure with composition similar to venous vasculature, with fenestrated thin endothelium surrounded by connective tissue ²⁴, ³³, ³⁰. After drainage through the trabecular meshwork and the Schlemm’s canal, aqueous humor continues through collector channels into the episcleral venous system which deposits into the main venous system ²⁴, ³³, ³⁰.

Resistance to outflow through the trabecular meshwork and Schlemm’s canal has been documented although it is poorly understood, yet resistance remains an important factor in regulating intraocular pressure and the pathogenesis of glaucomatous processes. In humans, up to 75% of aqueous outflow resistance is contributed by the trabecular meshwork while the remaining 25% is due to resistance beyond Schlemm’s canal ²⁴. The rate of outflow is directly influenced by iris and ciliary muscles which contract and relax based on cholinergic innervation and pharmacodynamics ²⁴, ³³, ³⁰, ²⁹, ³⁴. In ciliary contraction, the trabecular meshwork and Schlemm’s canal dilate, decreasing resistance and increasing outflow ²⁴, ³³, ³⁰, ²⁹, ³⁴. The rate of outflow is also influenced by intraocular pressure, with higher intraocular pressure altering the structure of endothelial lining in Schlemm’s canal to increase the number of porous vacuoles allowing increased outflow ²⁴, ³³, ³⁰, ²⁹, ³⁴. However, it is still debated if this finding substantially contributes to increasing outflow in glaucomatous eyes ²⁴, ³³, ³⁰, ²⁹, ³⁴.

The unconventional pathway involves drainage into the orbital vasculature, vortex veins and ciliary lymphatics, contributing up to 25-40% of total aqueous outflow in cynomolgus and vervet monkey models. The uveoscleral pathway involves diffusion into the sclera and episcleral through the orbital vasculature. The uveovortex pathway involves osmotic absorption of fluid through the choroid, passing into the vortex veins ³³. Lastly, the uveolymphatic pathway involves drainage into lymphatic vessels within the ciliary body, although the extent of drainage under normal physiological conditions remains controversial ³³. In addition, the unconventional pathway also includes corneal, iridial and retinal routes, albeit less clinically significant ³⁵. Regardless of downflow pathway, all unconventional paths require drainage through the interstitial spaces of the ciliary muscle ³³, ³⁵. Resistance also exists within the unconventional pathway likely due to ciliary muscle tone, as seen with changes in outflow in the setting of pilocarpine, increasing ciliary tone and decreasing flow, and atropine, decreasing ciliary tone and increasing flow ³³, ³⁵. Therefore, the unconventional pathways are also clinically important in moderating intraocular pressure, and serve as a potential target in glaucoma therapy.

Figure 5. Normal aqueous outflow

Footnotes: The ciliary body is a structure that sits directly behind the iris (the colored part of your eye). One of ciliary body’s jobs is to create an important fluid called aqueous humor, a fluid that nourishes the cornea and lens. Aqueous humor flows through a specific route into the front of the eye (the anterior chamber). This route allows aqueous humor to send important nutrients and oxygen to other parts of the eye, such as the lens and cornea. The aqueous humor is produced behind the iris, flows into the anterior chamber through the pupil, and exits the eye between the iris and cornea via the trabecular meshwork, a specialized eye tissue located at the chamber angle of the eye next to the cornea ³⁶. In a healthy eye, this is a constant process. The ciliary body is always producing aqueous humor, and 80%-90% aqueous humor is always draining through the trabecular meshwork. The trabecular meshwork is a specialized spongy tissue in the anterior chamber of the eye that regulates the outflow of aqueous humor ³⁶. The trabecular meshwork acts as a filter, controlling how quickly aqueous humor drains out of the eye through a structure called Schlemm’s canal, ultimately maintaining intraocular pressure (IOP). The canal of Schlemm, also known as Schlemm’s canal or the scleral venous sinus, is a circular, lymphatic-like vessel in the eye that drains aqueous humor from the anterior chamber into the episcleral blood vessels. The canal of Schlemm and the trabecular meshwork (TM) play a crucial role in maintaining intraocular pressure (IOP) by facilitating the outflow of aqueous humor. Too much aqueous humor production or obstruction of its outflow causes a rise in intraocular pressure (IOP) that can lead to glaucoma.

Childhood Glaucoma types

According to the Childhood Glaucoma Research Network (CGRN) classification, childhood glaucoma is classified into primary glaucoma, secondary glaucoma and glaucoma suspect (Figure 6) ².

1. Primary childhood glaucoma encompasses primary congenital glaucoma (PCG) and juvenile open-angle glaucoma (JOAG)
   • Primary congenital glaucoma (PCG) is further classified as:
     • Neonatal onset (0–1 month of age),
     • Infantile onset (1–24 months of age),
     • Late onset or late recognition of disease (>2 years of age),
     • Spontaneously arrested primary congenital glaucoma (PCG). Spontaneously arrested primary congenital glaucoma (PCG) was diagnosed in the presence of buphthalmos and Haab striae, with normal intraocular pressure (IOP), normal-appearing optic discs, and no corneal edema ³⁸.
   • Juvenile open-angle glaucoma (JOAG) is defined as a diagnosis of open-angle glaucoma between age 4 to less than 40 years of age, not exhibiting features of primary congenital glaucoma (PCG) (i.e., buphthalmos, Haab striae). Individuals were further reported to have normal-tension glaucoma (NTG, described as maximum recorded IOP ≤ 21 mmHg) or high-tension glaucoma (HTG, maximum recorded IOP > 21 mmHg) in the affected eye/s, where possible.
2. Secondary childhood glaucoma is classified based on the underlying pathology. Secondary childhood glaucoma includes glaucoma associated with nonacquired ocular anomalies (e.g., Axenfeld-Rieger spectrum, iris hypoplasia, aniridia), glaucoma associated with nonacquired systemic disease (e.g., phacomatoses, Juvenile Idiopathic Arthritis [JIA]), and glaucoma associated with acquired conditions (e.g., uveitis, trauma, or intraocular surgery). Glaucoma following cataract surgery is classified separately ³⁹.
   • Glaucoma associated with acquired conditions in which glaucoma is secondary to a condition that is not present at birth.
   • Glaucoma associated with nonacquired ocular anomalies in which glaucoma is secondary to a nonacquired condition that is predominantly ocular.
   • Glaucoma associated with nonacquired systemic disease in which glaucoma develops in the presence of a disease that is predominantly systemic, with or without ocular manifestations.
   • Glaucoma following cataract surgery in which cataract surgery precedes glaucoma onset regardless of any coexisting ocular or systemic abnormality.

As per the Childhood Glaucoma Research Network (CGRN) classification, individuals were classified as having glaucoma associated with nonacquired ocular anomalies, even in the presence of systemic disease, if the disorder was predominantly ocular ². This includes individuals with Peters’ anomaly or Axenfeld-Rieger spectrum (ARS) ². Peters anomaly is a rare congenital disorder characterized by central corneal opacity with a relatively clear peripheral cornea, often with iris and lens adhesions ⁴⁰. Peters anomaly can have associated systemic abnormalities like cleft lip, cleft palate, short stature, abnormal ears, and intellectual disability ⁴⁰. Individuals with only posterior embryotoxon and no systemic features were not considered to have Axenfeld-Rieger spectrum (ARS) as per the 9th Consensus Report of the World Glaucoma Association ². When an individual had anterior segment dysgenesis (ASD) that did not fit a specific phenotype, experts used the term “unclassified ASD” as recommended by Idrees et al ⁴¹. Individuals with primary angle-closure glaucoma were classified as having glaucoma associated with nonacquired ocular anomalies because this entity is caused by anatomic disorders of the iris, lens, and retrolenticular structures ⁴².

Figure 6. Childhood Glaucoma types

Footnotes: Childhood Glaucoma Research Network and World Glaucoma Association algorithm for the classification of childhood glaucoma.

Abbreviations: AL = axial length; C/D = cup-disc; JOAG = juvenile open-angle glaucoma; ROP = retinopathy of prematurity; VF = visual field

What is Glaucoma Suspect?

Eye specialist (ophthalmologist) will refer to someone as a “glaucoma suspect” if they think the person might be showing early signs of glaucoma such as higher than normal eye pressure called ocular hypertension but have no signs of optic nerve damage. Glaucoma suspects have no symptoms to suggest eye disease. They are usually identified as glaucoma suspects during routine checks by their optometrist. Many people suspected of having glaucoma at this stage turn out not to have it at all, but some do develop it in time and it is these people who can benefit the most from timely treatment. Their ophthalmologist (eye specialist) may notice something different about their optic nerve. Most “glaucoma suspects” have no symptoms. That is why you need to be carefully monitored by your ophthalmologist if you are a glaucoma suspect. An ophthalmologist can check for any changes over time and begin treatment if needed.

If someone has a very high intraocular pressure (high IOP) or very advanced optic nerve damage then the diagnosis of glaucoma is usually straightforward. However sometimes it is not entirely clear whether someone has glaucoma or not. The early signs of glaucoma can be subtle, and many glaucoma patients have a normal pressure.

There is no single test that is 100% effective in confirming the diagnosis of glaucoma all the time. Sometimes the only way to be sure that someone has glaucoma is to arrange follow up eye examinations every 4-6 months or so to work out whether progressive damage is occurring to the optic nerve in one or both eyes. Features in the examination which might lead to a patient being classified as a ‘glaucoma suspect’ include (glaucoma suspect requires at least one criteria) ²:

• Intraocular pressure (IOP) >21 mm Hg on two separate occasions
• A ‘suspicious’ optic disc appearance on examination such as ‘cupping’ of the disc or thinning of the neuro-retinal rim or nerve fiber layers.
• Unusual or defective visual fields
• Increased corneal diameter or axial length in the setting of normal intraocular pressure (IOP)

These are changes that can be seen with glaucoma, but can also be seen in other conditions such as farsightedness (myopia) where it may be a variation of normal.

Other risk factors for glaucoma such as a strong family history of glaucoma but without definite changes to the optic nerve as yet. Generally speaking, “glaucoma suspects” will not show any visual field defects on testing, or may show some field defects which are not yet entirely convincing as evidence of glaucoma. If you are a ‘glaucoma suspect’, the most important treatment is good follow-up care.

It is very important that someone suspected of experiencing the early onset of glaucoma has regular eye checks to make sure there is no continuing damage to the optic nerve. Even though a person is not yet receiving any treatment for glaucoma, she or he may still risk losing their vision if in fact they do turn out to have glaucoma. Thus it is very important to maintain follow-up care. Typically for a low-risk glaucoma suspect, this may require visits every 6 to 12 months. At each follow-up visit your eye doctor will check your vision and eye pressure, and examine the front and back of your eye, paying careful attention to the appearance of your optic nerves.

To examine the structure of the optic nerve, your doctor will perform a careful examination in the office, obtain optic nerve imaging, and obtain a baseline set of optic nerve photographs. To examine the function of the optic nerve, an automated visual field test we be implemented with the help of a technician, who will instruct you on the correct way to perform the test. All of these tests may be repeated at yearly intervals (or more or less frequently, as determined by your eye doctor) to assess if there are changes or “progression” over time. The follow-up visits are crucial to maintaining optimal eye health.

Sometimes eye doctors are on the fence about whether to start treatment, and it is only through repeat follow-up visits that they get a sense of whether or not someone has glaucoma. Usually a person thought to be a “glaucoma suspect” will not be treated for the condition until the diagnosis is confirmed. Typically, glaucoma advances slowly so its progress can be tracked safely without treatment until the diagnosis is confirmed.

If you’re a “glaucoma suspect” and needed treatment, initial treatment options may include topical eye drops or laser treatment of the drainage angle to increase the amount of fluid draining from the eye, both of which can lower the eye pressure. The decision to treat is often not a cut-and-dry one; your ophthalmologist will assess all of your risk factors, your examination findings, and seek your input as to whether to treat or continue to observe your eyes over time. Some patients prefer to “watch and wait” or are worried about the side effects of treatment, while others may be more risk-averse and would rather begin treatment and have peace of mind. There are some glaucoma risk calculators available but most eye doctors would agree that these may aid in diagnosis and assessment, but will not replace your doctor’s clinical judgment.

Childhood glaucoma causes

There are many causes of childhood glaucoma. It can be hereditary or it can be associated with other eye disorders.

• If childhood glaucoma cannot be attributed to any other cause, other noticeable eye defects or systemic problem, it is classified as primary congenital glaucoma. The cause of primary congenital glaucoma is not completely understood, though there is significant research to suggest that the trabecular meshwork is immature and compressed. Studies suggest that the normal posterior migration of embryonic neural crest cells destined to become the trabecular meshwork is abnormally halted ¹². The drainage angle where the inside of the sclera (the white of your eye) and the outer edge of your iris meet of children with primary congenital glaucoma is described as immature, thick, and compressed. High intraocular pressures (IOP) are believed to be a consequence of increased resistance to aqueous outflow in this abnormal trabecular meshwork. Researchers have identified several gene mutations that can lead to primary congenital glaucoma. Mutations in the CYP1B1 (cytochrome P450 family 1 subfamily B member 1) gene are the predominant genetic anomalies linked to primary congenital glaucoma ¹³.
• If childhood glaucoma is a result of another eye disorder, eye injury, or other disease, it is classified as secondary childhood glaucoma.
  • Associated with eye abnormalities e.g., Axenfeld-Rieger syndrome, aniridia (a rare genetic eye disorder characterized by the complete or partial absence of the iris, the colored part of the eye), iridotrabecular dysgenesis, Peter’s anomaly, sclerocornea (a rare, non-progressive, congenital condition where the cornea, normally transparent, becomes opaque and blends with the sclera, the white part of the eye), microcornea (a congenital condition where the cornea, the transparent front part of the eye, is smaller than normal, with a horizontal diameter of less than 10-11 mm), microphthalmos (a developmental disorder of the eye where one or both eyes are abnormally small and have anatomical malformations), ectopia lentis, persistent fetal vasculature, oculodermal melanocytosis, posterior polymorphous dystrophy,
  • Associated with systemic abnormalities e.g., chromosomal disorders like trisomy 21 (Down syndrome), connective tissue disorders such as Marfan syndrome, Stickler syndrome (a group of genetic disorders that primarily affect connective tissues, particularly in the face, eyes, ears, and joints), phakomatoses (a group of genetic disorders also known as neurocutaneous syndromes or neuro-oculo-cutaneous syndromes characterized by systemic hamartomas, primarily affecting the central nervous system, eyes, and skin) common examples include neurofibromatosis (types 1 and 2), Sturge-Weber syndrome, tuberous sclerosis, Lowe syndrome and von Hippel-Lindau disease
  • Glaucoma secondary to acquired causes e.g., retinopathy of prematurity, eye trauma, intraocular tumors, uveitis, eye inflammation, lens‑induced (with/without pupillary block), steroid-induced, intraocular infections, maternal rubella (congenital rubella syndrome), raised episcleral venous pressure
  • Glaucoma after surgery for congenital cataract.

Childhood glaucoma commonly starts with a defect in the way your child’s eye develops. The most common defect is in the trabecular meshwork, the tissue that the eye fluids (aqueous humor) drain through. When the trabecular meshwork doesn’t develop right, the aqueous humor fluids don’t drain properly. The buildup of fluids (aqueous humor) causes pressure in your child’s eye, which damages their optic nerve. It can also cause their cornea to enlarge, stretch, tear and scar. This process is progressive. How fast it progresses depends on how severe the defect in your child’s eye is, how much fluid (aqueous humor) is building up and how high the pressure is inside the eye (intraocular pressure [IOP]). When glaucoma appears in young infants, it’s because these conditions were already progressing during fetal development. When symptoms appear later, it’s because these conditions were less severe at birth, so they took longer to build up.

Primary congenital glaucoma

Most cases of primary congenital glaucoma are sporadic without a family history of the disease ⁴, ⁶, ¹, ⁴³. The significant risk factors for primary congenital glaucoma are consanguineous marriage also known as cousin marriage (a marriage between two individuals related by blood, typically first or second cousins, or closer), genetic predisposition, and first-degree relatives (including siblings) with glaucoma. Approximately 90% of cases belong to this category. About 10-40% are familial with an autosomal recessive inheritance pattern with incomplete penetrance ranging from 40% to 100% ², ⁴. Autosomal dominant inheritance has also been reported ⁴⁴.

Mutations in the CYP1B1 (cytochrome P450 family 1 subfamily B member 1) gene are the predominant genetic anomalies linked to primary congenital glaucoma ¹³. The CYP1B1 (cytochrome P450 family 1 subfamily B member 1) gene is essential for the formation of the trabecular meshwork and the anterior portion of the eye. The CYP1B1 gene codes for an enzyme that metabolizes compounds vital for the developing eye, such as fatty acids and vitamins ⁴⁵, and is expressed in fetal and adult neuroepithelium and ciliary body ², ⁴⁶. Severe trabecular meshwork atrophy is seen in mouse models deficient of CYP1B1 ⁴⁷. In zebrafish, CYP1B1 has been found to indirectly affect neural crest migration to the anterior segment and angle by playing a role in ocular fissure closure ⁴⁸. While the exact mechanism by which CYP1B1 mutations causes primary congenital glaucoma is unknown, scientists know that levels of a protein product of this gene are inadequate for appropriate embryogenic ocular development, resulting in goniodysgenesis. A twin study demonstrated that CYP1B1 gene activity may be implicated in a common pathway primary congenital glaucoma, juvenile open-angle glaucoma (JOAG), and primary open angle glaucoma (POAG). Recent studies propose that the CYP1B1 mutation may also interfere with the ability of retinal ganglion cells to respond to the stress generated by high intraocular pressure (IOP) and the resultant increase in reactive oxygen species ⁴⁹, ⁵⁰. CYP1B1 mutations are associated with 15-20% of primary congenital glaucoma cases in Japan and the United States, 75-100% of cases in Saudi Arabia, and all cases in Slovakia Roma ⁵¹, ⁵².

Additional implicated genes, including LTBP2 (latent transforming growth factor beta binding protein 2), are located next to the GLC3C locus ⁵³, ⁵⁴. These genetic mutations cause a dysfunctional trabecular meshwork, obstructing proper drainage of aqueous fluid and increasing intraocular pressure (IOP). Several gene loci have been linked to primary congenital glaucoma, which includes GLC3A, GLC3B, GLC3C, GLC3D, and GLC3E. Locus GLC3A has been linked to the CYP1B1 gene ⁵⁵.

Mutations in CYP1B1 (cytochrome P450 family 1 subfamily B member 1) gene are most commonly responsible for autosomal recessively inherited cases ⁵⁶. A recent systematic review reported that CYP1B1 was the most common gene mutation reported in the current literature and that the other gene variants related to childhood glaucoma included MYOC (myocilin), LTBP2, FOXC1 (forkhead box C1), PITX2 (paired-like homeodomain transcription factor 2), ANGPT1 (angiopoietin 1) and TEK (or receptor tyrosine kinase) ⁵⁷.

Currently, the chance of identifying a genetic cause is 40% when genetic testing is done ⁵⁸.

Studies from Western countries have reported primary congenital glaucoma incidences ranging from 1 per 10,000 to 1 per 30,000 live births ⁵⁹. The incidence is reportedly as high as 1/2500 in countries like Saudi Arabia. Slovakian Roma have the greatest incidence at 1/1250 ⁶⁰. The higher incidence in particular countries and ethnic groups is related to the higher prevalence of consanguineous marriages, particularly in those with frequent cousin-cousin marriages.

Approximately 65% to 80% of cases of primary congenital glaucoma are bilateral ⁵⁸. A male-to-female ratio of 3:2 has been reported in studies from the United States and Europe ²² A Japanese study quoted a male-to-female ratio of 6:5 in patients with CYP1BI mutation and 19:2 without the mutation ⁶¹. Several studies have reported that glaucoma accounted for 7% to 18% of children registered in blind schools ⁶², ⁶³. Asia, India, and Saudi Arabia have a mean presentation age of 3 to 4 months compared to 11 months in Western countries ⁶⁴. primary congenital glaucoma appears earlier in high-incidence ethnicities.

Risk factors for developing primary congenital glaucoma

The only known risk factors are genetic – consanguinity and affected siblings. Parents of primary congenital glaucoma patients should be aware that the chance of a second child with primary congenital glaucoma is a small but real risk that usually is no more than 3%. If two children have the disease, then the risk of subsequent children increases to as high as 25%, with the assumption of autosomal recessive inheritance ²². In 2018, Yu-Wai-Man et al ⁵⁸ compiled the clinical utility gene card for primary congenital glaucoma which describes situations for which gene testing may be useful. Carriers of the CYP1B1 gene mutation and double null CYP1B1 alleles are, on average, more likely to have higher intraocular pressure (IOP) and require more surgeries ⁴⁵.

Primary congenital glaucoma pathophysiology

The primary pathophysiologic process in primary congenital glaucoma is the defect in the development of the trabecular meshwork and the anterior chamber angle. This hampers the aqueous outflow through the anterior chamber and increases intraocular pressure (IOP). In 1955 and 1966, Barkan ⁶⁵ and Worst ⁶⁶ proposed that the presence of an imperforate membrane at the angle of the anterior chamber impeded the aqueous outflow; this was later disproved. The obstruction site is trabecular, as opposed to pretrabecular. The isolated maldevelopment of the trabecular meshwork, known as isolated trabeculodysgenesis, is the fundamental disease ⁶⁷.

The formation of an immature angle is believed to stem from the developmental arrest of tissues originating from neural crest cells during the third trimester of gestation. The degree of angle abnormalities is contingent upon the point at which angle development is halted ⁶⁸. The pathophysiology is believed to result from compacted thick trabecular sheets that merge and inhibit the posterior movement of the iris during the development of the anterior portion. The trabecular sheets position the iris more anteriorly, leading to the iris’ characteristic “high” insertion in children with primary congenital glaucoma.

Currently, the most accepted theory of the pathogenesis of primary congenital glaucoma proposed by Anderson states that excessive or premature accumulation of collagenous beams within the trabecular meshwork prevents normal insertion of the ciliary body and iris ⁶⁹. This results in an anteriorly inserted iris root and ciliary muscle, which can obstruct the trabecular meshwork, and narrow or completely compress the Schlemm canal elevating intraocular pressure (IOP) ⁷⁰, ⁶⁹. Increased intraocular pressure (IOP) leads to the typical symptoms of buphthalmos (enlargement of the eye) and Haab striae (breaks in the Descemet membrane). Histopathological and electron microscopic studies of primary congenital glaucoma have demonstrated obstruction through the outflow pathway ⁷⁰. Frequently, the ciliary muscle is inserted high on the trabecular meshwork. Moreover, a detailed framework analysis has shown an excessive amount of collagen in the trabecular meshwork. Other studies have demonstrated fibrillary collagen fibers, elastin fibers, and ground substances in the intervening trabecular meshwork and the canal of Schlemm ⁷¹. The microscopic observations explain the clinical manifestation of elevated intraocular pressure (IOP) and optic nerve impairment.

More recently, ultrasound biomicroscopy and anterior segment optical coherence tomography have been used to determine angle abnormalities in primary congenital glaucoma patients ⁷².

Childhood glaucoma prevention

There is no known way to prevent primary congenital glaucoma. Early detection and treatment are essential to maximize visual potential. A family history of glaucoma and a parental consanguineous marriage are essential elements to consider when considering a diagnosis of primary congenital glaucoma ⁷³.

In the future, prenatal genetic screening may emerge as a preventative measure. It can be offered to parents in at-risk populations, such as those with family history or in consanguineous relationships in areas with higher primary congenital glaucoma prevalence (Slovakia, Saudi Arabia, China, etc.). Parents with unborn children who test positively for mutations in CYP1B1 on genetic screening can be alerted about the potential need for urgent surgical management soon after birth ⁴⁵.

Childhood glaucoma signs and symptoms

Childhood glaucoma symptoms may not be as obvious in children. The following are the most common symptoms of childhood glaucoma. However, each child may experience symptoms differently. Symptoms may include:

• Excessive tearing (epiphora)
• Eye(s) that is sensitive to light (photophobia)
• Closure of one or both eyes in the light
• Cloudy, enlarged cornea (cloudy cornea)
• One eye may be larger than the other (bupthalmos)
• Vision loss

The classic triad of childhood glaucoma symptoms includes:

1. Epiphora (watery eyes, tearing).
2. Photophobia (light sensitivity).
3. Blepharospasm (uncontrollable eyelid twitching).

Other signs of childhood glaucoma may include:

• Buphthalmos (enlarged eyeballs or ox-eye).
• Bluish discoloration of the eyeball.
• Whitening or clouding of the cornea.

You may or may not be able to tell that your child has vision issues, like:

• Blurry vision (astigmatism).
• Nearsightedness (myopia).
• Favoring one eye (anisometropia).

An eye exam might reveal further signs of glaucoma, like:

• Corneal edema (swelling).
• Tears in the cornea.
• Corneal scarring.

Children usually have signs and symptoms in both eyes. But sometimes, they appear only in one.

If the eye pressure increases rapidly, there may be pain and discomfort. Parents may notice that the child becomes irritable, fussy, and develops a poor appetite. Early detection and diagnosis is very important to prevent loss of vision. The symptoms of glaucoma may resemble other eye problems or medical conditions. Always consult your child’s doctor for a diagnosis.

Childhood glaucoma complications

Untreated intraocular pressure (IOP) or delayed treatment in an infant eye may lead to severe complications and significant visual impairment in addition to permanent optic nerve damage and glaucomatous visual field defects. High intraocular pressure (IOP) causes corneal edema and corneal stretching with development of Haab striae. With prolonged corneal edema, both diffuse and focal overlying Haab striae, the cornea can become permanently opacified. Buphthalmos with axial elongation, and Haab striae cause abnormally high refractive errors including myopia and astigmatism, that can impair vision both by blurring vision and causing refractive amblyopia, which can be exacerbated by anisometropia in unilateral cases. In severe buphthalmos, with continued stretching, the lens could dislocate, and risk of retinal complications increases (i.e. lacquer cracks and retinal detachments). Overcoming these complications can be difficult in severe cases. Corneal transplantation for corneal opacification is avoided if possible due to high risk of failure and complications in young children.

Childhood glaucoma diagnosis

The diagnosis of childhood glaucoma can often be made clinically via thorough and precise ophthalmologic assessment, even without an accurate measurement of intraocular pressure (IOP). The hallmark of primary congenital glaucoma, however, is an elevated intraocular pressure (IOP) and ocular stretching in the absence of other ocular and systemic conditions that can cause glaucoma, such as Axenfeld-Reiger syndrome, aniridia, or surgical removal of cataract in infancy (i.e. glaucoma following cataract surgery) ⁷⁴ .

The clinical diagnosis of primary congenital glaucoma can be difficult, especially when a child does not cooperate with intraocular pressure (IOP) measurement. If a reliable intraocular pressure (IOP) measurement is elevated in the setting of other classic signs of ocular stretching, then the diagnosis of glaucoma is made, and if no other ocular or systemic developmental anomalies are seen, then primary congenital glaucoma is the diagnosis. The presence of Haab striae suggests congenital glaucoma, and if seen without ocular developmental anomalies or systemic syndromes, then primary congenital glaucoma is the diagnosis. If intraocular pressure (IOP) is normal with Haab striae, then one may have a case of spontaneously arrested primary congenital glaucoma, which still needs to be followed over time for elevated intraocular pressure (IOP) ⁶.

Medical History

Primary congenital glaucoma patients often present to the physician’s office due to abnormal appearance of the eyes such as a cloudiness or a blue tint to the eyes, or patient behavior such as eye rubbing or shying away from light. While there may be tearing, there is no ocular discharge and usually no eye redness. The patients are otherwise healthy. A positive family history is helpful but often is not present since most cases are sporadic.

Physical Examination

The clinical examination must include ⁷⁵:

• Fixation of light: The patient’s ability to fixate and follow light should be tested with each eye separately. There may be exotropia (where one or both eyes turn outward, away from the nose) due to poor fixation and nystagmus in long-standing cases.
• Sclera: The sclera(e) may appear bluish in color because of high myopia, scleral thinning, and exposure to underlying uveal tissue ⁷⁶.
• Cornea: Corneal examination might reveal signs of corneal enlargement or buphthalmos. Normal corneal size from birth to 6 months should be between 9.5 to 11.5 mm. A size of greater than 12 mm should raise the suspicion of glaucoma. A corneal diameter of more than 13 mm in any child older than 6 months indicates corneal enlargement. The slit-lamp examination may reveal horizontal or oblique tears and breaks in the Descemet membrane called Haab striae (see Figure 4). Another critical finding is corneal edema. This usually starts as epithelial edema and then gradually involves the deeper layers of the cornea, occasionally causing permanent opacities impairing vision profoundly ⁷⁷.
• Anterior chamber: The anterior chamber is usually deep.
• Iris: Iridodonesis, ectropion uvea, hypoplasia, or any atrophic patches may be present ⁷⁸.
• Pupil: The pupil may be oval, dilated, and ischemic.
• Lens: The clinician should evaluate for lenticular opacities or lens subluxation due to excessive stretching of zonules ⁷⁹.
• Optic disc: This typically demonstrates reversible cupping in the early stages. Later stages may present with an enlarged cup-to-disc ratio or even atrophy ⁸⁰, ⁸¹.
• Intraocular pressure (IOP): Intraocular pressure (IOP) is usually elevated at presentation and can be measured using a pneumotonometer in the outpatient setting ⁷⁴.

Childhood glaucoma signs

The main clinical signs of childhood glaucoma include elevated intraocular pressure (IOP) >21 mmHg, corneal edema and/or enlargement of the eye with buphthalmos, and Haab striae. The intraocular pressure (IOP) at presentation is usually between 30-40 mmHg, though it can be outside this range ⁸². Intraocular pressure (IOP) in the low-20s mmHg is acceptable if the optic nerve is healthy and the patient’s eye growth is within normal limits, but may not be if there are other more severe signs of primary congenital glaucoma.

With intraocular pressure (IOP) in the 30-40s mmHg, the cornea becomes cloudy due to diffuse and/or focal edema. As in adult eyes, the endothelial cell layer cannot pump fluid out of the cornea in an eye with elevated intraocular pressure (IOP). In young children however, there is the additional insult of corneal stretching from the high intraocular pressure (IOP) causing not only enlargement of the cornea, but Descemet breaks, leading to “striae,” which are areas of bare stroma bordered by two separated edges of Descemet membrane that become ridges due to deposition of hyaline ²². These are called Haab striae and are associated with acute overlying focal corneal edema when the intraocular pressure (IOP) is high. They occur in about 25% of primary congenital glaucoma eyes presenting at birth, and more than 60% of primary congenital glaucoma eyes identified at 6 months of age ²³. There may be single or multiple, and are oriented horizontally or obliquely. After normalization of intraocular pressure (IOP), corneal edema may clear; however, Haab striae remain and may be associated with corneal scarring. The poorly controlled cases of primary congenital glaucoma may end up with dense stromal opacification even after intraocular pressure (IOP) is controlled.

A newborn’s cornea is typically 9.5-10.5 mm in diameter and increases to 10.0-11.5 mm by age 1 ⁸³. Any diameter above 12.0 mm before 1 year of age suggests an abnormality, especially if there is asymmetry between the two eyes. If the diameter is greater than 13 mm at any age, glaucoma suspicion should be high. Along with corneal stretching in the setting of elevated IOP, there is stretching of the scleral wall and all tissues within the eye leading to buphthalmos. Corneal enlargement stops around age 3 years, while sclera can continue to stretch up to age 10 years of age ²².

Other signs related to the eye distension include abnormally deep anterior chamber, myopia (mainly due to elongation and enlargement of the eye), astigmatism (from Haab striae and corneal stretching), anisometropia (almost always present in unilateral primary congenital glaucoma), and optic nerve cupping.

The optic nerve cupping in very young children may be seen solely due to optic canal stretching and posterior bowing of the lamina cribrosa without a decrease in the neuroretinal rim ⁸⁴, ⁸⁵. When the IOP is normalized, there can be notable reversal of cupping. While cupping may resolve, retinal nerve fiber layer damage, if present, is permanent. In older children and those with advanced glaucoma, cupping occurs due to neuroretinal rim tissue loss, especially at the vertical disk poles ²².

Any asymmetry between eyes in the aforementioned signs should raise suspicion of glaucoma. Lastly, amblyopia, either deprivation or both, may also be present with the other signs mentioned above.

Diagnostic procedures

The main diagnostic test for primary congenital glaucoma is the measurement of the intraocular pressure (IOP), which should be done prior to instilling dilating drops. In a cooperative infant or young child, this measurement can be obtained in the clinic setting with a Perkins applanation tonometer, Tono-pen (a portable Mackay-Marg-type tonometer) and/or Icare rebound tonometer. In older patients, standard Goldmann applanation tonometry can be performed. A pneumotonometer may be useful to confirm intraocular pressure (IOP) during examination under anesthesia or in clinic if available, and may be less influenced by corneal abnormalities. A Schiötz indentation tonometry is not recommended in these patients due to under- or overestimation of intraocular pressure (IOP) in childhood glaucoma ⁸⁶, ⁸⁷. For the uncooperative child, an examination under anesthesia should be performed.

Of note, the Icare rebound tonometer has decreased the need for examinations under anesthesia as it does not require a topical anesthetic ⁸⁸. Two models available in the United States (Icare TAO1i and Icare ic100) require the patient to be upright, while the newest model, recently approved in the US (Icare ic200), allows measurement in a supine patient. The IOP measured by Icare in cooperative, awake children with known or suspected glauacoma, has been shown to be within 3 mmHg of IOP obtained by Goldmann applanation tonometry in 63% and is higher than measured by Goldmann applanation tonometry in 75% of children ⁸⁹. By contrast, Icare tonometry may under-measure the IOP compared to Tono-pen readings in the setting of corneal edema ⁹⁰.

Because anesthetic agents variably alter the intraocular pressure (IOP), with most lowering intraocular pressure (IOP), measurements should be obtained as soon as possible after induction of anesthesia and before intubation. If the intraocular pressure (IOP) is actually elevated, it often remains greater than 20 mmHg under anesthesia, which suggests glaucoma. The normal intraocular pressure (IOP) is lower in infants and young children than adults. A newborn has an average intraocular pressure (IOP) of 10-12 mm Hg, increasing to 14 mm Hg by age 7 or 8 years of age. An asymmetric measurement or an elevated intraocular pressure (IOP) measurement in the presence of other clinical signs helps make the diagnosis of glaucoma.

Corneal diameter measurement is another key diagnostic procedure for primary congenital glaucoma. Some providers check horizontal diameters only, while some check horizontal and vertical diameters. If there is pannus or scarring obscuring the limbus, the measurement may not be accurate. In the office a millimeter ruler can be placed above the eyes and if the child is not cooperative, a close-up digital photograph can be taken with the ruler in place, and a measurement can be made from the photo. This is most amenable to horizontal corneal diameter measurement. While under anesthesia, calipers with the tips placed at the limbus 180 degrees apart are used across the widest diameter, and then measured with a graduated ruler to check the measurement. Ideally, the measurement can be estimated to the nearest 0.25 mm ².

Examination for Haab striae is done with an oblique slit beam with a portable slit lamp if the patient is younger or under anesthesia, or on a regular slit lamp in the clinic if the patient is older. Retroillumination can also be used to identify Haab striae. . In older patients with treated primary congenital glaucoma, corneal endothelial protuberances and hyperproliferation of the Descemet membrane/pre-Descemet’s layer complex have been demonstrated with anterior segment OCT (ASOCT). These may demarcate areas in which the edges of the Descemet membrane have re-approximated during the healing process ⁷⁷.

If a view through the cornea allows it, gonioscopy is done in clinic if tolerated, ideally a Sussman (or similar) indirect gonioscopy lens as it fits easily between a young child’s small palpebral fissure. Using a gonioscopy lens without a handle may be easier as it allows the examiner to hold open the eyelids while placing the lens. More commonly, for initial diagnosis of primary congenital glaucoma, gonioscopy is performed under under anesthesia with a Koeppe or similar direct gonioscopy lens and portable slit lamp. There are different sized Koeppe lenses to fit different corneal diameters. The Koeppe lens is best handled with a glove to avoid fingerprint smudges. The Koeppe lens cup is filled with balanced salt solution and placed quickly on the eye or placed on the eye and tilted with one edge abutting the sclera while filling the space between the lens and eye with solution. Then a binocular microscope such as the portable slit lamp is angled towards the angle of interest and the lens can be shifted slightly toward the angle to optimize the view.

Gonioscopy in these cases helps guide surgical planning in cases of primary congenital glaucoma, and may also identify other angle abnormalities which might identify other secondary glaucoma types, for example Axenfeld-Rieger anomaly (many irido-corneal attachments with anteriorly placed Schwalbe line). Infants with primary congenital glaucoma usually do not have a visible scleral spur because the peripheral iris inserts into the trabecular meshwork (in contrast to normal infants whose peripheral iris and ciliary body have recessed to the scleral spur or posterior to it). There may also be scalloped edges of the peripheral iris and pale peripheral iris stroma in front of the angle causing a “morning mist” appearance. If there are peripheral anterior synechiae, posterior embryotoxon, or other abnormalities, then the diagnosis is unlikely primary congenital glaucoma. Gonioscopy photographs can be taken by instilling the eye with coupling gel and angling the camera lens (i.e. RetCam) obliquely toward the angle of interest and adjusting the focus until the angle comes into clear view.

Axial length is measured with A-scan ultrasonography, ideally using the immersion and not contact method, either in clinic or under anesthesia. It is best done under anesthesia, during baseline examination to determine if the axial length is greater than normal for the patient’s age, and repeated approximately every 3-4 months to assess if the growth rate is greater than average. Of note, measuring axial length itself is not an indication for examination under anesthesia if a patient is otherwise doing well, and can be performed at intervals when examination under anesthesia is needed for clinical management. Sampaolesi and Kiskis provided linear regressions from data of normal children. Sampaolesi used immersion A-scans and found the normal axial length for a one-month-old lies between 17.25 mm (5th percentile) and 20.25 mm (95th percentile). Sampaolesi also recommended that axial length be measured after dilation with cycloplegic drops ⁹¹, ².

Optic nerve evaluation is performed with either indirect or direct ophthalmoloscopy with attention to the cup-to-disc ratio. In the setting of a small pupil, a magnified view of the nerve can be obtained by using a direct ophthalmoscope through a Koeppe gonioscopy lens on the eye. Fundus photography is also recommended for comparisons between serial examinations. B-scan ultrasonography is recommended if the cornea does not allow fundus examination to rule out posterior disease. Severe optic nerve cupping may sometimes be noted on the posterior B-scan.

Pachymetry is used to measure central corneal thickness. The central cornea may be thicker due to corneal edema, and has also shown to be thinner in primary congenital glaucoma patients without corneal edema, likely due to stretching of their tissues ⁹². Other small studies have shown either no significant difference in central corneal thickness between normal eyes and eyes treated for primary congenital glaucoma, or the central corneal thickness was thicker in eyes treated for primary congenital glaucoma than in normal eyes ⁹³, ⁹⁴. Corneal hysteresis and corneal resistance factor have been found to be lower in eyes with primary congenital glaucoma compared to normal eyes ⁹³, ⁹⁴.

Perimetry can be attempted starting around age 7-8 years of age if the patient does not have nystagmus, cognitive impairment or severe vision loss. Quicker testing algorithms such as SITA-FAST may allow children to perform more reliably ⁹⁵. Goldman perimetry can be very helpful in young children.

Standard tabletop optical coherence tomography (OCT) can be considered once a child can be examined at the regular slit lamp to evaluate the retinal nerve fiber layer and ganglion cell layer. It may be helpful especially if the child cannot perform perimetry. While devices currently do not carry normative data for children, studies have collected data on normal children ⁹⁶, ⁹⁷, ⁹⁸, ⁹⁹. Handheld and mounted spectral-domain OCT devices are emerging technologies that can be used during examination under anesthesia ¹⁰⁰, ¹⁰¹.

Childhood glaucoma diagnostic criteria

Childhood glaucoma diagnostic criteria per Childhood Glaucoma Research Network definition ²:

Definition of childhood glaucoma required two or more of the main categories (1‑5)

• Intraocular pressure (IOP) >21 mm Hg (investigator discretion if examination under anaesthesia data alone)
• Optic disc cupping
  • Progressive increase in cup‑disc ratio
  • Cup‑disc asymmetry of ≥0.2 when disc sizes are similar
  • Focal rim thinning
• Corneal findings
  • Haab striae
  • Diameter
    • >11 mm in newborn
    • >12 mm in child <1 year of age
    • >13 mm any age
• Progressive myopia /myopic shift coupled with an increase in ocular dimensions out of keeping with normal growth
• Reproducible visual field defect that is consistent with glaucomatous optic neuropathy with no other observable reason for the visual field defect

Childhood glaucoma differential diagnosis

The differential diagnoses of childhood glaucoma can be remembered by the mnemonic STUMPED, which includes the following conditions:

• S: Sclerocornea, congenital hereditary stromal dystrophy ¹⁰². This uncommon disorder is characterized by corneal opacification and may be mistaken for primary congenital glaucoma. A flattened cornea with no concomitant elevation in IOP or optic nerve impairment defines Sclerocornea.
• T: Trauma, tears in Descemet membrane or endothelial (ie, from forceps).
• U: Ulcer caused by various factors, including viral, fungal, bacterial, neurotrophic, and pythium (a parasitic aquatic oomycete that causes vision-threatening keratitis) ¹⁰³, ¹⁰⁴, ¹⁰⁵
• M: Metabolic disorders, eg, mucolipidoses, mucopolysaccharidosis, tyrisinosis
• P: Peters anomaly, an uncommon disorder characterized by central corneal opacity and adherence of the iris to the cornea, may manifest with glaucoma; the principal anomaly is the corneal-lenticular contact ¹⁰⁶
• E: Endothelial dystrophy, congenital hereditary endothelial dystrophy, posterior polymorphous dystrophy, Fuchs dystrophy ¹⁰⁷
• D: Dermoid ¹⁰⁸

Other significant differentials which should be kept in mind include:

• Interstitial keratitis
• High myopia
• Megalocornea
• Corneal abrasion
• Messman dystrophy
• Reis-Buckler dystrophy
• Retinoblastoma
• Retinopathy of prematurity
• Persistent primary hyperplastic vitreous
• Traumatic glaucoma ¹⁰⁹
• Congenital rubella syndrome
• Sturge-Weber syndrome
• Aniridia
• Optic disc pit
• Optic atrophy ¹¹⁰
• Coloboma

Childhood glaucoma treatment

It is important for treatment of childhood glaucoma to start as early as possible. The management of childhood glaucoma is directed toward lowering and controlling the intraocular pressure (IOP) and treating the secondary complications such as refractive change and amblyopia that develop during the course of the disease.

Childhood glaucoma treatment may include:

• Medications. Some medications cause the eye to produce less fluid, while others lower pressure by helping fluid drain from the eye.
• Surgery. The purpose of surgery is to create a new opening for fluid to leave the eye. Surgical procedures are performed by using microsurgery or lasers.

Both medications and surgery have been successfully used to treat childhood glaucoma. However, surgery is the primary treatment modality for primary congenital glaucoma. In managing secondary childhood glaucoma, medications is the first-line treatment ¹⁴.

Surgical procedures used to treat childhood glaucoma include the following:

• Trabeculotomy and goniotomy.
  • Trabeculotomy is a surgical procedure, primarily used in the treatment of childhood glaucoma, that creates a new drainage opening in the eye’s trabecular meshwork, improving the outflow of aqueous humor and reducing the intraocular pressure (IOP).
  • Goniotomy is a microinvasive glaucoma surgery (MIGS) technique that improves fluid flow in the eye to lower intraocular pressure (IOP). A goniotomy involves making a small incision within the trabecular meshwork, the eye’s natural drainage system, to create a more efficient pathway for fluid outflow. This procedure can be used to treat conditions like childhood glaucoma.
• Trabeculectomy. Trabeculectomy is a surgical procedure that involves the removal of part of the trabecular meshwork drainage system, allowing the fluid to drain from the eye. Trabeculectomy works by creating a new drainage pathway for the fluid (aqueous humor) within the eye, allowing it to drain into a space beneath the outer layer of the eye (conjunctiva). This new pathway, called a bleb, helps reduce eye pressure and can slow or prevent further vision loss.
• Iridotomy. Iridotomy is a surgical procedure to treat or prevent angle-closure glaucoma, a condition where the iris (colored part of the eye) blocks the drainage angle, leading to increased eye pressure. The eye surgeon may use a laser to create this hole. Laser iridotomy involves using a laser to create a small hole in the iris, allowing fluid to flow freely and preventing or relieving pressure build-up.
• Cyclophotocoagulation. Cyclophotocoagulation is a laser procedure that uses a laser beam to freeze selected areas of the ciliary body – the part of the eye that produces aqueous humor – to reduce the production of fluid and reduce intraocular pressure (IOP). Cyclophotocoagulation is a type of cyclodestruction procedure, meaning it aims to reduce intraocular pressure (IOP) by damaging the ciliary body, a key part of the eye that produces aqueous humor. This type of surgery may be performed with severe cases of childhood glaucoma.

The primary treatment of primary congenital glaucoma is angle surgery, either goniotomy or trabeculotomy, to lower intraocular pressure (IOP) by improving aqueous outflow. If angle surgery is not successful, trabeculectomy enhanced with mitomycin C or glaucoma implant surgery with a Molteno, Baerveldt, or Ahmed implant can be performed. In refractory cases, cycloablation can be performed using an Nd:YAG laser, diode laser, or cryotherapy, with diode laser being the most widely used device. Medications, either topically or orally, is typically used as a temporizing measure prior to surgery and to help decrease corneal clouding to facilitate goniotomy, and to supplement intraocular pressure (IOP) control after surgery.

Medications

Medications for primary congenital glaucoma is typically used as an adjunct (add-on) to surgery. Most medications in the United States have not been approved for children, however many studies have been performed that inform doctors on their safety and efficacy in children. Timolol (a non-selective beta blocker) is the first choice in pediatric glaucoma. In cases with insufficient reduction of the intraocular pressure (intraocular pressure (IOP)), the combination of timolol once a day and dorzolamide twice a day brings about a good control of the intraocular pressure (IOP). Both medications are effective and well tolerated. The alpha2-agonists have more and potentially serious adverse effects in children and are contraindicated for children younger than 2 years of age. Latanoprost tends to be less effective in lowering intraocular pressure (IOP) in children than in adults ¹¹¹.

• Beta-blockers (beta-adrenergic antagonists): Topical beta-blockers play a large role in primary congenital glaucoma treatment and include timolol (non-selective beta-1 and beta-2 blocker, concentrations of 0.1% available in some countries, 0.25% and 0.5% solutions, and 0.25% and 0.5% gel-forming solution), and betaxolol (selective beta-1-blocker, concentrations of 0.25% and 0.5% solutions). Given potentially high plasma levels of the medication from topical instillation in small children, the lowest concentration available should be initiated first. The solution drops are approved for BID dosing though may be just as effective dosed once in the morning. The gel-forming solutions are approved for once daily dosing. Beta-blockers typically reduce intraocular pressure (IOP) by 20-30%. Side effects are mainly systemic and include respiratory distress, caused by apnea or bronchospasm (which may present as coughing instead of wheezing), and bradycardia. Beta-blockers should be avoided in patients with bradycardia, second- or third-degree atrioventricular block, and active asthma or “reactive airways.” Betaxolol may be less likely to cause pulmonary distress (e.g. asthma attacks) and cardiac side effects ¹¹².
• Carbonic anhydrase inhibitors: Oral carbonic anhydrase inhibitors include acetazolamide (Diamox, dose 10-20 mg/kg/day divided into 3 or 4 doses) and methazolamide (Neptazane, dose < 2 mg/kg/day, divided into 2 doses) ¹¹³, ². Acetazolamide can be prepared in a flavored syrup (have the pharmacist crush the tablets and suspend the powder in syrup) with a concentration of 50 mg/ml for ease of use. Children can also take the tablet crushed in applesauce or something similar. It reduces the intraocular pressure (IOP) about 20-35%. Side effects occur in >40% of patients and include lethargy, decreased appetite, weight loss, gastrointestinal discomfort, diarrhea and metabolic acidosis. Topical carbonic anhydrase inhibitors include dorzolamide 2% (Trusopt) and brinzolamide 1% (Azopt) drops twice a day (BID) or three times a day (TID). These medications may produce less reduction in intraocular pressure (IOP) (about 25%) than oral carbonic anhydrase inhibitors, but also appear to have fewer systemic side effects. Rarely, side effects can occur, particularly in premature infants, such as metabolic acidosis ¹¹⁴. Topical carbonic anhydrase inhibitors ideally should be avoided or used as a later option in the setting of compromised corneas, especially of a corneal transplant ².
• Combination beta-blocker/carbonic anhydrase inhibitor: Timolol 0.5%-dorzolamide 2% (Cosopt) drop twice a day (BID) has been shown to be effective in reducing intraocular pressure (IOP) in children requiring more than one topical medication. It is approved for twice a day (BID) dosing, but cautious use in young children is warranted due to the higher concentration of timolol.
• Adrenergic agonists (avoid or use with caution in children younger than age 6 years or weight less than 20 kg): Apraclonidine 0.5% (Iopidine) and brimonidine (Alphagan, Alphagan P, 0.1%, 0.15%, 0.2%) are alpha-2 selective agonists and are dosed twice a day (BID) to three times a day (TID). Their effectiveness has not been studied specifically for primary congenital glaucoma. The side effects in children limit their use. Due to being highly lipophilic, brimonidine passes through the blood-brain barrier potentially causing severe sleepiness, respiratory depression, apnea and coma, especially in neonates and infants, thus it is strictly contraindicated in patients 2 years old or younger. It may also cause bradycardia, hypotension, hypotonia, and hypothermia. Apraclonidine is more hydrophilic which reduces its blood-brain barrier penetration and thus has fewer central nervous system side effects than brimonidine. It must still be used with caution and is best used for short- or intermediate-term intraocular pressure (IOP) lowering. Tachyphylaxis and ocular allergy limit its effectiveness long-term.
• Combination beta-blocker/alpha-2 adrenergic agonists: Timolol 0.5%-brimonidine 0.2% (Combigan) must not be prescribed to children if there is a contraindication to the individual components.
• Prostaglandin analogs: Latanoprost 0.005% (Xalatan), travoprost 0.004% (Travatan), bimatoprost 0.01% (Lumigan), and tafluprost (Zioptan, preservative-free) are dosed nightly. Latanoprost reduces the intraocular pressure (IOP) in primary congenital glaucoma 15-20% ¹¹⁵. While the FDA has not approved prostaglandin analogs in children, Europe has approved latanoprost for children. Side effects mainly include lash growth, conjunctival injection, and less commonly iris pigmentation alteration, allergy, uveitis and periocular hyperpigmentation. Side effects seem more prominent with use of travoprost and bimatoprost and less with latanoprost. Long-term side effects are still unknown in children. Prostaglandin-related periorbitopathy has been described in children ¹¹⁶. This class of medication is relatively contraindicated when active inflammation or uveitis is present.
• Combination beta-blocker/prostaglandin analog: Available in countries outside the United States.
• Miotic agents: These do not play much of a role in primary congenital glaucoma likely due to their immature angle anatomy and high ciliary muscle insertion. They include echothiophate, phospholine iodide (irreversible cholinesterase and pseudocholinesterase inhibitors) and pilocarpine (direct parasympathomimetic). Miotic are useful perioperatively for angle surgery. Pilocarpine (0.5-6%, most common 1-2%) is dosed once to four times a day, usually 2-3 times a day after angle surgery. Side effects include miosis, decreased heart rate, apnea, sweating, and hypersalivation, and theoretically may induce cataract and retinal detachment.
• Modified prostaglandin analogs and rho-associated protein kinase inhibitors: Latanoprostene bunod (Vyzulta) and netarsudil (Rhopressa) have not been studied in patients younger than 18 years of age.

Doctors can start with a either a carbonic anhydrase inhibitor, beta-blocker or prostaglandin analog, or a combination, and progressively add another medication class, keeping in mind medications are generally a temporizing measure prior to surgery. If prescribed before initial surgery, medications should not be used without fairly frequent follow-up, and ideally surgery performed within 2 weeks of primary congenital glaucoma diagnosis. Early discussion preparing family and caregivers for surgery is necessary. Medications should be continued until surgery, and may help maximize corneal clearing by reducing the intraocular pressure (IOP). After surgery, medications may still be needed as an adjunct and family and caregivers should be made aware of this. Compliance may be an issue when the medication regimen becomes complex and should be addressed. primary congenital glaucoma requires lifelong serial measurements of intraocular pressure (IOP), corneal diameter, axial length, refractive error, and optic nerve cupping. If an adequate assessment is not possible in the outpatient clinic, an examination under anesthesia should be performed.

Surgery

Surgery is the mainstay of treatment for patients with primary congenital glaucoma. The type of surgical procedure depends on the disease severity, cornea clarity, and surgeon’s choice and experience. There are 4 major surgical options for primary congenital glaucoma; however once the diagnosis of primary congenital glaucoma is established, angle surgery is the first procedure of choice to incise/open the trabecular meshwork with the hope of allowing aqueous flow from the anterior chamber directly into Schlemm canal. It is generally agreed that angle surgery is most successful in infantile-onset primary congenital glaucoma, and less so in newborn or late-recognized primary congenital glaucoma. Goniotomy is preferred by some surgeons when the cornea is clear enough to permit visualization of anterior segment structures (although some prefer trabeculotomy regardless of the corneal clarity, see below). An incision is made across the trabecular meshwork under direct gonioscopic visualization using a goniotomy knife (Swan knife, needle-knife, disposable 25-gauge needle on a syringe) and surgical goniotomy lens (i.e. Barkan or other goniotomy lens). Traditionally, it is first performed nasally, however modifications can be made to complete it temporally as well at one surgical session. If a surgeon is comfortable with devices and modified techniques such as using the Kahook dual blade, Trabectome, gonioscopy-assisted transluminal trabeculotomy with suture or lighted microcatheter, or Omni, these devices can be used safely to perform a goniotomy in children, however it is not recommended to use these devices in a pediatric eye prior to extensive experience in an adult eye. There is no data to suggest these modified techniques do better than traditional goniotomy or trabeculotomy. Complications include hyphema, anterior chamber shallowing, peripheral anterior synechiae, and rarely, iridodialysis, cyclodialysis, cataract, scleral perforation, epithelial ingrowth, and retinal detachment ², ¹¹⁷.

When the cornea is not clear enough to permit visualization of the angle, or if preferred due to technical factors or surgeon experience or preference, trabeculotomy ab externo (“trabeculotomy”) is the procedure of choice. Access to Schlemm canal is obtained externally via a partial scleral flap to allow cannulation of Schlemm canal. The older technique opened ~90 degrees of Schlemm canal with a curved rigid pronged probe called a trabeculotome, which can then be rotated gently into the anterior chamber to incise through the trabecular meshwork. A trabeculotome curved in the opposite direction can then be used to cannulate another 90 degrees of Schlemm canal and complete 180 degrees of trabeculotomy. Alternatively, and preferred by many angle surgeons at this time, a 6-0 polypropylene (Prolene) suture or an illuminated microcatheter can be threaded into the entire Schlemm canal and pulled across the anterior chamber to complete a 360-degree trabeculotomy. Complications include hyphema, unintentional filtering blebs, choroidal detachment, cyclodialysis, iridodialysis, lens injury, and infection.

Traditional goniotomy and trabeculotomy ab externo (incising 2 quadrants) have success rates ranging for goniotomy 30-65% and for trabeculotomy 40-80%, with success reported as low as 10% to as high as 94% ², ¹¹⁸.

Combined trabeculotomy and trabeculectomy (CTT) can be performed if Schlemm canal could not be cannulated or prior trabeculotomy failed, in which a trabeculectomy is added to the trabeculotomy by removing a block of tissue in the scleral flap bed followed by a surgical iridectomy as done in regular trabeculectomy. Mitomycin C may be used with care. Combined trabeculotomy and trabeculectomy (CTT) can be an initial surgical procedure, especially in Indian and Middle Eastern patients ¹¹⁹, ¹²⁰.

Filtering surgery is considered when one or more angle surgeries have failed and includes traditional trabeculectomy with or without mitomycin C and glaucoma drainage device implantation. Trabeculectomy may be best done using techniques of the Moorfields Safer Surgery System, including fornix-based conjunctival flaps, small radial cuts, mitomycin C under the sclera flap and subconjunctival tissue with wider spread to enhance posterior aqueous flow and reduce bleb-related complications. Use of an anterior chamber maintainer in all cases and releasable sutures are also recommended ¹²¹, ¹²², ¹²³. EX-PRESS mini glaucoma shunts are not used commonly in primary congenital glaucoma as safety and efficacy have not been established long-term in young children. Severe complications of trabeculectomy include vitreous loss, ectasia, scleral collapse, retinal detachment, and phthisis. The child is also at lifelong risk of complications and infection including bleb leak, wound rupture, blebitis, and endophthalmitis.

Reported success rates for trabeculectomy performed for primary congenital glaucoma range between 50-87% ². The risk of failure is 5.6 times higher in patients age 1 year or less ¹²⁴. The higher risk of failure in advanced primary congenital glaucoma young patients is due to buphthalmos, lack of scleral rigidity, and highly active healing and scarring.

When trabeculectomy fails or is not a desirable option, then the other filtering option with glaucoma drainage device (GDD) surgery or cyclodestructive procedures are the next surgical choices. All models of glaucoma drainage devices (Molteno, Baerveldt, and Ahmed valve) can be used in primary congenital glaucoma patients, and glaucoma drainage devices can be implanted safely in neonates with attention to eye and implant parameters. Generally, it is advisable to use a fornix incision with conjunctival and Tenon capsule incision 8 mm posterior to the limbus, and double-layer closure with running 8-0 polyglactin (Vicryl) suture on a vascular needle. The flexible implants (Baerveldt and Ahmed) can be trimmed posteriorly so as to prevent plate-optic nerve touch. The amount to trim can be calculated with the online Freedman-Margeta GDD calculator (https://people.duke.edu/~freed003/GDDCalculator/) ¹²⁵. Some surgeons place the first tube inferior nasal to preserve conjunctiva superiorly for possible trabeculectomy when the patient is older, however others prefer superior temporal placement of the first tube, for better efficacy, and are able to perform successful trabeculectomy superior nasal at a future time. Complications from glaucoma drainage devices are many and include those of trabeculectomy plus cornea-tube touch, tube erosion through the conjunctiva or cornea, implant migration, and cataract. Infection rates are low ¹²⁶. The Ahmed valve may additionally fail due to fibrovascular ingrowth into the valve chamber ¹²⁷.

Success rates vary widely for primary congenital glaucoma and childhood glaucoma. For the Molteno, the range is 56-95%, with slightly higher success with the double-plate implant compared to the one-plate implant ¹²⁸, ¹²⁹. The Baerveldt success rates range from 80-95% at 12 months, decreasing to < 50% by 60 months ¹³⁰, ¹³¹. The Ahmed glaucoma valve has about a 55% success rate at 5 years ¹³², ¹³³.

Cyclodestructive procedures are useful tools in managing refractory primary congenital glaucoma after all other options have been tried, to reduce aqueous production. Results are unpredictable and complications exist. Laser cyclophotocoagulation (CPC) has largely replaced cyclocryotherapy, and diode laser is preferred to Nd:YAG laser due to decreased adverse events such as sympathetic ophthalmia. Transscleral and endoscopic application of laser are both options, with endoscopic preferred if the eye anatomy allows. Transscleral Micropulse-cyclophotocoagulation may have less severe complications than traditional transscleral cyclophotocoagulation and be as effective in children ¹³⁴, though further research is needed. The limbal anatomy may be distorted and blind application of transscleral cyclophotocoagulation may be better guided with ultrasound biomicroscopy ¹³⁵. A general rule of thumb for all cyclodestructive procedures is to maintain 1-2 clock hours of untouched ciliary processes, even after repeated sessions, thus careful documentation of treated areas is recommended. Rare complications include hypotony, retinal detachment, visual loss, and phthisis.

Success for transscleral cyclophotocoagulation ranges from 30-79% with retreatment in ~70% of patients, and has been comparable to implanting a second glaucoma drainage device (GDD) in children ¹³⁶, ¹³⁷, ¹³⁸, ¹³⁹. Endoscopic cyclophotocoagulation (ECP) has been reported to be 64% successful at 1 year, and 16% by 5 years, with sequential endoscopic cyclophotocoagulation (ECP) bringing the rate up to 81% at 1 year, and 34% at 5 years ¹⁴⁰, ¹⁴¹.

Surgical Complications

Surgical complications include:

• Hyphema
• Shallow anterior chamber ¹⁴²
• Peripheral anterior synechiae
• Iridodialysis
• Cyclodialysis (a condition where the longitudinal ciliary muscle fibers separates from the scleral spur, the area where the muscle attaches to the eye’s wall) ¹⁴³
• Cataract ¹⁴⁴, ¹⁴⁵
• Epithelial ingrowth
• Choroidal detachment
• Retinal detachment
• Phthisis bulbi

Filtering Procedure-Related Complications:

• Over or under-filtration
• Blebitis
• Vitreous loss
• Scleral collapse
• Scleral flap leak
• Tube lens touch
• Endothelial decompensation from tube cornea touch
• Tube erosion
• Implant migration
• Diplopia from implant-related restrictions
• Endophthalmitis

Cyclodestructive Procedure-Related Complications:

• Hypotony
• Retinal detachment ¹⁴⁶
• Phthisis

Anesthesia-Related Complications:

• Oculocardiac reflex
• Anaphylaxis
• Malignant hyperthermia
• Cardiovascular collapse
• Hepatic porphyria
• Hypoxic brain injury.

Postoperative and Rehabilitation Care

The children undergoing surgery should be started on topical steroids, either prednisolone 1% or dexamethasone 0.1% for 1 week each using an 8/7/6/5/4/3/2/1 tapering dosage. In addition, a topical antibiotic in the form of tobramycin 0.3% or 0.3% moxifloxacin or gatifloxacin 4 times per day for 20 days should be supplemented to prevent secondary infection. These patients will need close follow-ups postsurgery to look for signs of hypotony, inflammation, or infection. Moreover, the IOP needs to be recorded every 3 to 4 months for at least 2 years postsurgery.

Cycloplegic refraction will be needed every 6 months for these patients. Moreover, lifelong regular follow-up every 6 months is needed for intraocular pressure (IOP) monitoring and early detection of any surgery-related complications. Cases of failing angle or filtration surgery should be counseled for the need for glaucoma drainage device (GDD) and the risk of subsequent failure, amblyopia, blindness, and phthisis bulbi (a shrunken, disfigured, and non-functional eye that has undergone significant damage).

Surgical follow up

In the short term, patients require frequent follow up to follow response to treatment and monitor for hypotony, infection, and excessive inflammation. For young patients, or patients with less than 2 years of intraocular pressure (IOP) control, follow-up is recommended at least every 3-4 months. Regular life-long follow-up is needed (at least every 6 months) because even if long-term intraocular pressure (IOP) control from a surgical intervention is achieved, asymptomatic relapse can occur at any time and will need to be managed with medications or further surgery. Additionally, vision-threatening complications may occur at any time, especially after filtering surgeries.

Glaucoma drainage device (GDD) patency can be assessed with B-scan ultrasonography in the clinic ¹⁴⁷.

Childhood glaucoma prognosis

The prognosis for children with primary congenital glaucoma is quite variable, with some achieving good vision, while others go blind ⁶. While primary congenital glaucoma accounts for less than 0.01% of all patients with eye diseases, it has been blamed for 5% of childhood blindness worldwide ⁵⁸. Vision loss is secondary to corneal scarring or optic nerve damage, and often amblyopia in asymmetric or unilateral cases. Surgical management is the primary treatment modality. If intraocular pressure (IOP) is controlled, vision in the better eye ultimately can be 20/60 or better ¹⁴⁸, ¹⁴⁹.

A study from the United States showed a lack of progression following adequate treatment in 90.3% at 1 year, 83.1% at 5 years, 70.8% at 10 years, and 58.3% at 34 years ¹⁵⁰. Thus highlighting the importance of appropriate management and follow-ups for these patients. Another study showed that angle procedures were 90% successful among patients presenting between 2 months and 1 year of age, compared to 50% among those presenting either in infantile or late-onset or late-recognized cases ¹⁵¹.

Consideration must also be given to the burden on caregivers, whose actions likely will affect the patient’s prognosis. Recent studies have highlighted that one-third of primary congenital glaucoma caregivers could have moderate to severe depression, and quality of life is poorer for the caregiver if the patient is older and has had the disease longer ¹⁵², ¹⁵³.

1. Knight LSW, Ruddle JB, Taranath DA, et al. Childhood and Early Onset Glaucoma Classification and Genetic Profile in a Large Australasian Disease Registry. Ophthalmology. 2021 Nov;128(11):1549-1560. https://www.aaojournal.org/article/S0161-6420(21)00288-8/fulltext[↩][↩]
2. Weinreb R.N., Grajewski A.L., Papadopoulos M., Grigg J.,Freedman S.F. Childhood glaucoma: the 9th consensus report of the World Glaucoma Association. Netherlands: Kugler Publications, 2013.[↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩]
3. Xia Q, Zhang D, Zhuang Y, Dai Y, Jia H, Du Q, Wen T, Jiang Y. Animal Model Contributions to Primary Congenital Glaucoma. J Ophthalmol. 2022 May 26;2022:6955461. doi: 10.1155/2022/6955461[↩]
4. Kaur K, Zeppieri M, Gurnani B. Primary Congenital Glaucoma. [Updated 2024 Nov 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK574553[↩][↩][↩][↩]
5. Abu-Amero KK, Edward DP. Primary Congenital Glaucoma. 2004 Sep 30 [Updated 2017 Aug 17]. In: Adam MP, Feldman J, Mirzaa GM, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2025. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1135[↩]
6. Primary Congenital Glaucoma. https://eyewiki.org/Primary_Congenital_Glaucoma[↩][↩][↩][↩][↩][↩][↩]
7. Lingham G, Thakur S, Safi S, Gordon I, Evans JR, Keel S. A systematic review of clinical practice guidelines for childhood glaucoma. BMJ Open Ophthalmol. 2022 Jan 31;7(1):e000933. doi: 10.1136/bmjophth-2021-000933[↩]
8. Congenital Glaucoma. https://glaucoma.org/types/congenital-glaucoma[↩]
9. Glaucoma in Infants. https://www.rch.org.au/ophthal/patient_information/Glaucoma/[↩]
10. Yeung HH, Kumar-Singh R, Walton DS. Infantile Aphakic Glaucoma: A Proposed Mechanism. J Pediatr Ophthalmol Strabismus. 2022 Jul-Aug;59(4):236-242. doi: 10.3928/01913913-20210929-02[↩]
11. Jafer Chardoub AA, Zeppieri M, Blair K. Juvenile Glaucoma. [Updated 2024 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK562263[↩]
12. Alward, W.L.M. Glaucoma: The Requisites in Ophthalmology. St. Louis: Mosby Inc; 2000.[↩][↩]
13. Haddad A, Ait Boujmia OK, El Maaloum L, Dehbi H. Meta-analysis of CYP1B1 gene mutations in primary congenital glaucoma patients. Eur J Ophthalmol. 2021 Nov;31(6):2796-2807. doi: 10.1177/11206721211016308. Erratum in: Eur J Ophthalmol. 2024 Jul;34(4):NP71-NP72. doi: 10.1177/11206721231156301[↩][↩][↩]
14. Greco, A. et al., 2022, ‘Childhood Glaucoma and Medical Treatment: An Up to Date’, in G. L. Giudice (ed.), Vision Correction and Eye Surgery, IntechOpen, London. 10.5772/intechopen.100579.[↩][↩]
15. Feroze KB, Blair K, Patel BC. Buphthalmos. [Updated 2025 Jan 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK430887[↩][↩]
16. Beck AD. Diagnosis and management of pediatric glaucoma. Ophthalmol Clin North Am. 2001 Sep;14(3):501-12. doi: 10.1016/s0896-1549(05)70248-0[↩]
17. Mark HH. Buphthalmos: early glaucoma history. Acta Ophthalmol. 2011;89:591–594. doi: 10.1111/j.1755-3768.2009.01783.x[↩]
18. Bouhenni RA, Ricker I, Hertle RW. Prevalence and clinical characteristics of childhood Glaucoma at a tertiary care Children’s hospital. J Glaucoma. 2019;28:655–659. doi: 10.1097/IJG.0000000000001259[↩]
19. Vasileiadis GT, Frangouli O. Unilateral congenital buphthalmos. BMJ Case Rep. 2015 Jun 3;2015:bcr2015210979. doi: 10.1136/bcr-2015-210979[↩]
20. Kaushik S, Dhingra D, Joshi G, Bazgain K, Thattaruthody F, Pandav SS. Acute Hydrops in the Fellow Eye of Infants with Primary Congenital Glaucoma after Intraocular Pressure Reduction in 1 Eye. Ophthalmol Glaucoma. 2020 Jul-Aug;3(4):301-305. doi: 10.1016/j.ogla.2020.03.007[↩]
21. Haab striae in primary congenital glaucoma. https://eyerounds.org/atlas/pages/Haab/index.htm#gsc.tab=0[↩]
22. deLuise VP, Anderson DR. Primary infantile glaucoma (congenital glaucoma). Surv Ophthalmol. 1983 Jul-Aug;28(1):1-19. doi: 10.1016/0039-6257(83)90174-1[↩][↩][↩][↩][↩][↩]
23. Morin JD, Bryars JH. Causes of loss of vision in congenital glaucoma. Arch Ophthalmol. 1980 Sep;98(9):1575-6. doi: 10.1001/archopht.1980.01020040427005[↩][↩]
24. Goel M, Picciani RG, Lee RK, Bhattacharya SK. Aqueous humor dynamics: a review. Open Ophthalmol J. Sep 3 2010;4:52-9. doi:10.2174/1874364101004010052[↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩]
25. Toris CB, Koepsell SA, Yablonski ME, Camras CB. Aqueous humor dynamics in ocular hypertensive patients. J Glaucoma. 2002 Jun;11(3):253-8. doi: 10.1097/00061198-200206000-00015[↩][↩][↩][↩][↩]
26. Macknight AD, McLaughlin CW, Peart D, Purves RD, Carré DA, Civan MM. Formation of the aqueous humor. Clin Exp Pharmacol Physiol. 2000 Jan-Feb;27(1-2):100-6. doi: 10.1046/j.1440-1681.2000.03208.x[↩]
27. Ferreira SM, Lerner SF, Brunzini R, Evelson PA, Llesuy SF. Oxidative stress markers in aqueous humor of glaucoma patients. Am J Ophthalmol. 2004 Jan;137(1):62-9. doi: 10.1016/s0002-9394(03)00788-8[↩][↩]
28. Kaeslin MA, Killer HE, Fuhrer CA, Zeleny N, Huber AR, Neutzner A. Changes to the Aqueous Humor Proteome during Glaucoma. PLoS One. 2016 Oct 27;11(10):e0165314. doi: 10.1371/journal.pone.0165314[↩][↩]
29. Brubaker RF. The flow of aqueous humor in the human eye. Trans Am Ophthalmol Soc. 1982;80:391-474. https://pmc.ncbi.nlm.nih.gov/articles/instance/1312276/pdf/taos00019-0414.pdf[↩][↩][↩][↩][↩]
30. R TCYMT. Aqueous humor dynamics. In: DC CNL, ed. Atlas of Glaucoma. Second edition ed. Informa HK; 2007:13 – 28:chap 3.[↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩]
31. Kiel JW, Hollingsworth M, Rao R, Chen M, Reitsamer HA. Ciliary blood flow and aqueous humor production. Prog Retin Eye Res. Jan 2011;30(1):1-17. doi:10.1016/j.preteyeres.2010.08.001[↩][↩][↩][↩][↩]
32. Macknight AD, McLaughlin CW, Peart D, Purves RD, Carre DA, Civan MM. Formation of the aqueous humor. Clin Exp Pharmacol Physiol. Jan-Feb 2000;27(1-2):100-6. doi:10.1046/j.1440-1681.2000.03208.x[↩]
33. Johnson M, McLaren JW, Overby DR. Unconventional aqueous humor outflow: A review. Exp Eye Res. May 2017;158:94-111. doi:10.1016/j.exer.2016.01.017[↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩]
34. Roy Chowdhury U, Hann CR, Stamer WD, Fautsch MP. Aqueous humor outflow: dynamics and disease. Invest Ophthalmol Vis Sci. May 2015;56(5):2993-3003. doi:10.1167/iovs.15-16744[↩][↩][↩][↩]
35. Fautsch MP, Johnson DH. Aqueous humor outflow: what do we know? Where will it lead us? Invest Ophthalmol Vis Sci. Oct 2006;47(10):4181-7. doi:10.1167/iovs.06-0830[↩][↩][↩]
36. Trabecular Meshwork Research. https://ethier.gatech.edu/anterior-segmenttrabecular-meshwork-biomechanics[↩][↩]
37. J. Buffault, A. Labbé, P. Hamard, F. Brignole-Baudouin, C. Baudouin. The trabecular meshwork: Structure, function and clinical implications. A review of the literature. Journal Français
    d’Ophtalmologie, 2020, 43 (7), pp.e217-e230. https://hal.sorbonne-universite.fr/hal-02962228v1/document[↩]
38. Thau A, Lloyd M, Freedman S, Beck A, Grajewski A, Levin AV. New classification system for pediatric glaucoma: implications for clinical care and a research registry. Curr Opin Ophthalmol. 2018 Sep;29(5):385-394. doi: 10.1097/ICU.0000000000000516[↩]
39. Kong L, et al. An update on progress and the changing epidemiology of causes of childhood blindness worldwide. J AAPOS. 2012;16(6):501–507. doi: 10.1016/j.jaapos.2012.09.004[↩]
40. Jat NS, Tripathy K. Peters Anomaly. [Updated 2023 Aug 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK580540[↩][↩]
41. Idrees F, Vaideanu D, Fraser SG, Sowden JC, Khaw PT. A review of anterior segment dysgeneses. Surv Ophthalmol. 2006 May-Jun;51(3):213-31. doi: 10.1016/j.survophthal.2006.02.006[↩]
42. Weinreb RN, Aung T, Medeiros FA. The pathophysiology and treatment of glaucoma: a review. JAMA. 2014 May 14;311(18):1901-11. doi: 10.1001/jama.2014.3192[↩]
43. Wiggs JL, Pasquale LR. Genetics of glaucoma. Hum Mol Genet. 2017 Aug 1;26(R1):R21-R27. doi: 10.1093/hmg/ddx184[↩]
44. Lewis CJ, Hedberg-Buenz A, DeLuca AP, Stone EM, Alward WLM, Fingert JH. Primary congenital and developmental glaucomas. Hum Mol Genet. 2017 Aug 1;26(R1):R28-R36. doi: 10.1093/hmg/ddx205[↩]
45. Shah M, Bouhenni R, Benmerzouga I. Geographical Variability in CYP1B1 Mutations in Primary Congenital Glaucoma. J Clin Med. 2022 Apr 6;11(7):2048. doi: 10.3390/jcm11072048[↩][↩][↩]
46. Bejjani BA, Xu L, Armstrong D, Lupski JR, Reneker LW. Expression patterns of cytochrome P4501B1 (Cyp1b1) in FVB/N mouse eyes. Exp Eye Res. 2002 Sep;75(3):249-57. https://doi.org/10.1006/exer.2002.2025[↩]
47. Teixeira LB, Zhao Y, Dubielzig RR, Sorenson CM, Sheibani N. Ultrastructural abnormalities of the trabecular meshwork extracellular matrix in Cyp1b1-deficient mice. Vet Pathol. 2015 Mar;52(2):397-403. doi: 10.1177/0300985814535613[↩]
48. Williams AL, Eason J, Chawla B, Bohnsack BL. Cyp1b1 Regulates Ocular Fissure Closure Through a Retinoic Acid-Independent Pathway. Invest Ophthalmol Vis Sci. 2017 Feb 1;58(2):1084-1097. doi: 10.1167/iovs.16-20235[↩]
49. Suri F, Yazdani S, Narooie-Nejhad M, Zargar SJ, Paylakhi SH, Zeinali S, Pakravan M, Elahi E. Variable expressivity and high penetrance of CYP1B1 mutations associated with primary congenital glaucoma. Ophthalmology. 2009 Nov;116(11):2101-9. doi: 10.1016/j.ophtha.2009.04.045[↩]
50. Alghamdi A, Aldossary W, Albahkali S, Alotaibi B, Alrfaei BM. The loss of microglia activities facilitates glaucoma progression in association with CYP1B1 gene mutation (p.Gly61Glu). PLoS One. 2020 Nov 10;15(11):e0241902. doi: 10.1371/journal.pone.0241902[↩]
51. Schlötzer-Schrehardt U, Zenkel M, Küchle M, Sakai LY, Naumann GO. Role of transforming growth factor-beta1 and its latent form binding protein in pseudoexfoliation syndrome. Exp Eye Res. 2001 Dec;73(6):765-80. doi: 10.1006/exer.2001.1084[↩]
52. Hyytiäinen M, Keski-Oja J. Latent TGF-beta binding protein LTBP-2 decreases fibroblast adhesion to fibronectin. J Cell Biol. 2003 Dec 22;163(6):1363-74. doi: 10.1083/jcb.200309105[↩]
53. Ali M, McKibbin M, Booth A, et al. Null mutations in LTBP2 cause primary congenital glaucoma. Am J Hum Genet. 2009 May;84(5):664-71. doi: 10.1016/j.ajhg.2009.03.017[↩]
54. Suri F, Yazdani S, Elahi E. LTBP2 knockdown and oxidative stress affect glaucoma features including TGFβ pathways, ECM genes expression and apoptosis in trabecular meshwork cells. Gene. 2018 Oct 5;673:70-81. doi: 10.1016/j.gene.2018.06.038[↩]
55. Sarfarazi M, Akarsu AN, Hossain A, Turacli ME, Aktan SG, Barsoum-Homsy M, Chevrette L, Sayli BS. Assignment of a locus (GLC3A) for primary congenital glaucoma (Buphthalmos) to 2p21 and evidence for genetic heterogeneity. Genomics. 1995 Nov 20;30(2):171-7. doi: 10.1006/geno.1995.9888[↩]
56. Fan BJ, Wiggs JL. Glaucoma: genes, phenotypes, and new directions for therapy. J Clin Invest. 2010 Sep;120(9):3064-72. doi: 10.1172/JCI43085[↩]
57. Kumar A, Han Y, Oatts JT. Genetic changes and testing associated with childhood glaucoma: A systematic review. PLoS One. 2024 Feb 22;19(2):e0298883. doi: 10.1371/journal.pone.0298883[↩]
58. Yu-Wai-Man C, Arno G, Brookes J, Garcia-Feijoo J, Khaw PT, Moosajee M. Primary congenital glaucoma including next-generation sequencing-based approaches: clinical utility gene card. Eur J Hum Genet. 2018 Nov;26(11):1713-1718. doi: 10.1038/s41431-018-0227-y[↩][↩][↩][↩]
59. Tamçelik N, Atalay E, Bolukbasi S, Çapar O, Ozkok A. Demographic features of subjects with congenital glaucoma. Indian J Ophthalmol. 2014 May;62(5):565-9. doi: 10.4103/0301-4738.126988[↩]
60. Genĉík A. Epidemiology and genetics of primary congenital glaucoma in Slovakia. Description of a form of primary congenital glaucoma in gypsies with autosomal-recessive inheritance and complete penetrance. Dev Ophthalmol. 1989;16:76-115.[↩]
61. Ohtake Y, Tanino T, Suzuki Y, Miyata H, Taomoto M, Azuma N, Tanihara H, Araie M, Mashima Y. Phenotype of cytochrome P4501B1 gene (CYP1B1) mutations in Japanese patients with primary congenital glaucoma. Br J Ophthalmol. 2003 Mar;87(3):302-4. doi: 10.1136/bjo.87.3.302[↩]
62. Alabdulwahhab KM, Ahmad MS. Visual Impairment and Blindness in Saudi Arabia’s School for the Blind: A Cross-Sectional Study. Clin Optom (Auckl). 2020 Oct 7;12:169-173. doi: 10.2147/OPTO.S265293[↩]
63. Souma T, Tompson SW, Thomson BR, et al. Angiopoietin receptor TEK mutations underlie primary congenital glaucoma with variable expressivity. J Clin Invest. 2016 Jul 1;126(7):2575-87. doi: 10.1172/JCI85830[↩]
64. Badawi AH, Al-Muhaylib AA, Al Owaifeer AM, Al-Essa RS, Al-Shahwan SA. Primary congenital glaucoma: An updated review. Saudi J Ophthalmol. 2019 Oct-Dec;33(4):382-388. doi: 10.1016/j.sjopt.2019.10.002[↩]
65. Barkan O. Pathogenesis of congenital glaucoma: gonioscopic and anatomic observation of the angle of the anterior chamber in the normal eye and in congenital glaucoma. Am J Ophthalmol. 1955;40:1-11.[↩]
66. Worst JGF. The pathogenesis of congential glaucoma. An embryological and goniosurgical study. Springfield, Ill: Charles C. Thomas; 1966.[↩]
67. Mandal AK, Chakrabarti D. Update on congenital glaucoma. Indian J Ophthalmol. 2011 Jan;59 Suppl(Suppl1):S148-57. doi: 10.4103/0301-4738.73683[↩]
68. Mandal AK, Chakrabarti D, Gothwal VK. Approach to primary congenital glaucoma: A perspective. Taiwan J Ophthalmol. 2023 Oct 19;13(4):451-460. doi: 10.4103/tjo.TJO-D-23-00104[↩]
69. Anderson DR. The development of the trabecular meshwork and its abnormality in primary infantile glaucoma. Trans Am Ophthalmol Soc. 1981;79:458-85. https://pmc.ncbi.nlm.nih.gov/articles/instance/1312195/pdf/taos00020-0482.pdf[↩][↩]
70. Tawara A, Inomata H. Developmental immaturity of the trabecular meshwork in congenital glaucoma. Am J Ophthalmol. 1981 Oct;92(4):508-25. doi: 10.1016/0002-9394(81)90644-9[↩][↩]
71. García-Antón MT, Salazar JJ, de Hoz R, Rojas B, Ramírez AI, Triviño A, Aroca-Aguilar JD, García-Feijoo J, Escribano J, Ramírez JM. Goniodysgenesis variability and activity of CYP1B1 genotypes in primary congenital glaucoma. PLoS One. 2017 Apr 27;12(4):e0176386. doi: 10.1371/journal.pone.0176386[↩]
72. Pilat AV, Proudlock FA, Shah S, Sheth V, Purohit R, Abbot J, Gottlob I. Assessment of the anterior segment of patients with primary congenital glaucoma using handheld optical coherence tomography. Eye (Lond). 2019 Aug;33(8):1232-1239. doi: 10.1038/s41433-019-0369-3[↩]
73. Papadopoulos M, Cable N, Rahi J, Khaw PT; BIG Eye Study Investigators. The British Infantile and Childhood Glaucoma (BIG) Eye Study. Invest Ophthalmol Vis Sci. 2007 Sep;48(9):4100-6. doi: 10.1167/iovs.06-1350[↩]
74. Sihota R, Sidhu T, Agarwal R, Sharma A, Gupta A, Sethi A, Dada T, Pandey V. Evaluating target intraocular pressures in primary congenital glaucoma. Indian J Ophthalmol. 2021 Aug;69(8):2082-2087. doi: 10.4103/ijo.IJO_3473_20[↩][↩]
75. Mandal AK. Acute Corneal Hydrops in Children with Primary Infantile Glaucoma: A Report of 31 Cases over 23 Years at the LVPEI. PLoS One. 2016 Jun 1;11(6):e0156108. doi: 10.1371/journal.pone.0156108[↩]
76. Drechsler J, Lee A, Maripudi S, Kueny L, Levin MR, Saeedi OJ, Bazemore M, Karwoski B, Birdsong R, Martinez C, Jaafar MS, Yousaf S, Ahmed ZM, Madigan WP, Alexander JL. Corneal Structural Changes in Congenital Glaucoma. Eye Contact Lens. 2022 Jan 1;48(1):27-32. doi: 10.1097/ICL.0000000000000844[↩]
77. Gupta S, Mahalingam K, Singh A, Selvan H, Somarajan BI, Gupta V. Posterior corneal morphological changes in primary congenital glaucoma. Indian J Ophthalmol. 2022 Jul;70(7):2571-2577. doi: 10.4103/ijo.IJO_317_22[↩][↩]
78. Sihota R, Mahalingam K, Maurya AK, Sharma A, Bukke AN, Dada T. Primary congenital glaucoma: An iridotrabeculodysgenesis? Indian J Ophthalmol. 2024 Mar 1;72(3):328-334. doi: 10.4103/IJO.IJO_370_23[↩]
79. Walton DS. Chronic newborn primary congenital glaucoma with secondary lens subluxation. J Pediatr Ophthalmol Strabismus. 2009 Jul-Aug;46(4):200, 231. doi: 10.3928/01913913-20090706-02[↩]
80. Snehi S, Singh AK, Kaushik S. Acquired Lens Zonular Loss with Bean Pot Optic Disc Cupping in Congenital Glaucoma. Ophthalmol Glaucoma. 2023 Mar-Apr;6(2):159. doi: 10.1016/j.ogla.2023.01.001[↩]
81. Gupta V, James MK, Singh A, Kumar S, Gupta S, Sharma A, Sihota R, Kennedy DJ. Differences in Optic Disc Characteristics of Primary Congenital Glaucoma, Juvenile, and Adult Onset Open Angle Glaucoma Patients. J Glaucoma. 2016 Mar;25(3):239-43. doi: 10.1097/IJG.0000000000000154[↩]
82. Walton DS. Diagnosis and treatment of glaucoma in childhood. In: Epstein DL, editor. Chandler and Grant’s Glaucoma. 3rd ed. Phila: Lea & Febinger; 1986.[↩]
83. Kiskis AA, Markowitz SN, Morin JD. Corneal diameter and axial length in congenital glaucoma. Can J Ophthalmol. 1985 Apr;20(3):93-7.[↩]
84. Kessing SV, Gregersen E. The distended disc in early stages of congenital glaucoma. Acta Ophthalmol (Copenh). 1977 Jun;55(3):431-5. doi: 10.1111/j.1755-3768.1977.tb06119.x[↩]
85. Quigley HA. The pathogenesis of reversible cupping in congenital glaucoma. Am J Ophthalmol. 1977 Sep;84(3):358-70. doi: 10.1016/0002-9394(77)90680-8[↩]
86. Fayed MA, Chen TC. Pediatric intraocular pressure measurements: Tonometers, central corneal thickness, and anesthesia. Surv Ophthalmol. 2019 Nov-Dec;64(6):810-825. doi: 10.1016/j.survophthal.2019.05.003[↩]
87. Eisenberg DL, Sherman BG, McKeown CA, Schuman JS. Tonometry in adults and children. A manometric evaluation of pneumatonometry, applanation, and TonoPen in vitro and in vivo. Ophthalmology. 1998 Jul;105(7):1173-81. doi: 10.1016/S0161-6420(98)97016-6[↩]
88. Grigorian F, Grigorian AP, Olitsky SE. The use of the iCare tonometer reduced the need for anesthesia to measure intraocular pressure in children. J AAPOS. 2012 Dec;16(6):508-10. doi: 10.1016/j.jaapos.2012.07.004[↩]
89. Flemmons MS, Hsiao YC, Dzau J, Asrani S, Jones S, Freedman SF. Icare rebound tonometry in children with known and suspected glaucoma. J AAPOS. 2011 Apr;15(2):153-7. doi: 10.1016/j.jaapos.2010.11.022[↩]
90. McKee EC, Ely AL, Duncan JE, Dosunmu EO, Freedman SF. A comparison of Icare PRO and Tono-Pen XL tonometers in anesthetized children. J AAPOS. 2015 Aug;19(4):332-7. doi: 10.1016/j.jaapos.2015.04.004[↩]
91. Sampaolesi R, Caruso R. Ocular echometry in the diagnosis of congenital glaucoma. Arch Ophthalmol. 1982 Apr;100(4):574-7. doi: 10.1001/archopht.1982.01030030576003[↩]
92. Henriques MJ, Vessani RM, Reis FA, de Almeida GV, Betinjane AJ, Susanna R Jr. Corneal thickness in congenital glaucoma. J Glaucoma. 2004 Jun;13(3):185-8. doi: 10.1097/00061198-200406000-00002[↩]
93. Doozandeh A, Yazdani S, Ansari S, Pakravan M, Motevasseli T, Hosseini B, Yasseri M. Corneal profile in primary congenital glaucoma. Acta Ophthalmol. 2017 Nov;95(7):e575-e581. doi: 10.1111/aos.13357[↩][↩]
94. Zareei A, Razeghinejad MR, Salouti R. Corneal Biomechanical Properties and Thickness in Primary Congenital Glaucoma and Normal Eyes: A Comparative Study. Med Hypothesis Discov Innov Ophthalmol. 2018 Summer;7(2):68-72. https://pmc.ncbi.nlm.nih.gov/articles/PMC6146241[↩][↩]
95. Donahue SP, Porter A. SITA visual field testing in children. J AAPOS. 2001 Apr;5(2):114-7. doi: 10.1067/mpa.2001.113840[↩]
96. Salchow DJ, Oleynikov YS, Chiang MF, Kennedy-Salchow SE, Langton K, Tsai JC, Al-Aswad LA. Retinal nerve fiber layer thickness in normal children measured with optical coherence tomography. Ophthalmology. 2006 May;113(5):786-91. doi: 10.1016/j.ophtha.2006.01.036[↩]
97. Ahn HC, Son HW, Kim JS, Lee JH. Quantitative analysis of retinal nerve fiber layer thickness of normal children and adolescents. Korean J Ophthalmol. 2005 Sep;19(3):195-200. doi: 10.3341/kjo.2005.19.3.195[↩]
98. Hess DB, Asrani SG, Bhide MG, Enyedi LB, Stinnett SS, Freedman SF. Macular and retinal nerve fiber layer analysis of normal and glaucomatous eyes in children using optical coherence tomography. Am J Ophthalmol. 2005 Mar;139(3):509-17. doi: 10.1016/j.ajo.2004.10.047[↩]
99. Rao A, Sahoo B, Kumar M, Varshney G, Kumar R. Retinal nerve fiber layer thickness in children <18 years by spectral-domain optical coherence tomography. Semin Ophthalmol. 2013 Mar;28(2):97-102. doi: 10.3109/08820538.2012.760626[↩]
100. Rotruck JC, House RJ, Freedman SF, Kelly MP, Enyedi LB, Prakalapakorn SG, Lim ME, El-Dairi MA. Optical Coherence Tomography Normative Peripapillary Retinal Nerve Fiber Layer and Macular Data in Children 0-5 Years of Age. Am J Ophthalmol. 2019 Dec;208:323-330. doi: 10.1016/j.ajo.2019.06.025[↩]
101. Hsu ST, Chen X, Ngo HT, House RJ, Kelly MP, Enyedi LB, Materin MA, El-Dairi MA, Freedman SF, Toth CA, Vajzovic L. Imaging Infant Retinal Vasculature with OCT Angiography. Ophthalmol Retina. 2019 Jan;3(1):95-96. doi: 10.1016/j.oret.2018.06.017[↩]
102. Gouider D, Choura R, Mekni M, Sayadi J, Malek I, Nacef L. Sclerocornea: A rare ocular condition. J Fr Ophtalmol. 2021 Sep;44(7):1089-1091. doi: 10.1016/j.jfo.2021.05.001[↩]
103. Gurnani B, Christy J, Narayana S, Rajkumar P, Kaur K, Gubert J. Retrospective multifactorial analysis of Pythium keratitis and review of literature. Indian J Ophthalmol. 2021 May;69(5):1095-1101. doi: 10.4103/ijo.IJO_1808_20[↩]
104. Gurnani B, Narayana S, Christy J, Rajkumar P, Kaur K, Gubert J. Successful management of pediatric pythium insidiosum keratitis with cyanoacrylate glue, linezolid, and azithromycin: Rare case report. Eur J Ophthalmol. 2022 Sep;32(5):NP87-NP91. doi: 10.1177/11206721211006564[↩]
105. Gurnani B, Kaur K. Pythium Keratitis. [Updated 2023 Jul 17]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK573072[↩]
106. Raven ML, Rodriguez ME, Potter HD. Corneal Leukoma with Features of Both Sclerocornea and Peter’s Anomaly. Ophthalmology. 2016 Sep;123(9):1988. doi: 10.1016/j.ophtha.2016.05.011[↩]
107. Altamirano F, Ortiz-Morales G, O’Connor-Cordova MA, Sancén-Herrera JP, Zavala J, Valdez-Garcia JE. Fuchs endothelial corneal dystrophy: an updated review. Int Ophthalmol. 2024 Feb 12;44(1):61. doi: 10.1007/s10792-024-02994-1[↩]
108. Nusbaum L, Paul M, Maharshak I. [DEEP ORBITAL DERMOID CYSTS]. Harefuah. 2023 Feb;162(2):98-102. Hebrew.[↩]
109. Balamurugan S, Gurnani B, Kaur K, Gireesh P, Narayana S. Traumatic intralenticular abscess-What is so different? Indian J Radiol Imaging. 2020 Jan-Mar;30(1):92-94. doi: 10.4103/ijri.IJRI_369_19[↩]
110. Kaur K, Gurnani B, Devy N. Atypical optic neuritis – a case with a new surprise every visit. GMS Ophthalmol Cases. 2020 Feb 27;10:Doc11. doi: 10.3205/oc000138[↩]
111. Coppens G, Stalmans I, Zeyen T, Casteels I. The safety and efficacy of glaucoma medication in the pediatric population. J Pediatr Ophthalmol Strabismus. 2009 Jan-Feb;46(1):12-8. doi: 10.3928/01913913-20090101-05[↩]
112. Buckley MM, Goa KL, Clissold SP. Ocular betaxolol. A review of its pharmacological properties, and therapeutic efficacy in glaucoma and ocular hypertension. Drugs. 1990 Jul;40(1):75-90. doi: 10.2165/00003495-199040010-00005[↩]
113. Maren TH, Haywood JR, Chapman SK, Zimmerman TJ. The pharmacology of methazolamide in relation to the treatment of glaucoma. Invest Ophthalmol Vis Sci. 1977 Aug;16(8):730-42.[↩]
114. Capino AC, Dannaway DC, Miller JL. Metabolic Acidosis with Ophthalmic Dorzolamide in a Neonate. J Pediatr Pharmacol Ther. 2016 May-Jun;21(3):256-9. doi: 10.5863/1551-6776-21.3.256[↩]
115. Maeda-Chubachi T, Chi-Burris K, Simons BD, Freedman SF, Khaw PT, Wirostko B, Yan E; A6111137 Study Group. Comparison of latanoprost and timolol in pediatric glaucoma: a phase 3, 12-week, randomized, double-masked multicenter study. Ophthalmology. 2011 Oct;118(10):2014-21. doi: 10.1016/j.ophtha.2011.03.010[↩]
116. Kim JS, Blizzard S, Woodward JA, Leyngold IM, Liss J, Freedman SF. Prostaglandin-Associated Periorbitopathy in Children and Young Adults with Glaucoma. Ophthalmol Glaucoma. 2020 Jul-Aug;3(4):288-294. doi: 10.1016/j.ogla.2020.03.009[↩]
117. El Sayed Y, Esmael A, Mettias N, El Sanabary Z, Gawdat G. Factors influencing the outcome of goniotomy and trabeculotomy in primary congenital glaucoma. Br J Ophthalmol. 2021 Sep;105(9):1250-1255. doi: 10.1136/bjophthalmol-2018-313387[↩]
118. Huang H, Bao WJ, Yamamoto T, Kawase K, Sawada A. Postoperative outcome of three different procedures for childhood glaucoma. Clin Ophthalmol. 2018 Dec 17;13:1-7. doi: 10.2147/OPTH.S186929[↩]
119. Mandal AK, Gothwal VK, Nutheti R. Surgical outcome of primary developmental glaucoma: a single surgeon’s long-term experience from a tertiary eye care centre in India. Eye (Lond). 2007 Jun;21(6):764-74. doi: 10.1038/sj.eye.6702324[↩]
120. Khalil DH, Abdelhakim MA. Primary trabeculotomy compared to combined trabeculectomy-trabeculotomy in congenital glaucoma: 3-year study. Acta Ophthalmol. 2016 Nov;94(7):e550-e554. doi: 10.1111/aos.13018[↩]
121. Jayaram H, Scawn R, Pooley F, Chiang M, Bunce C, Strouthidis NG, Khaw PT, Papadopoulos M. Long-Term Outcomes of Trabeculectomy Augmented with Mitomycin C Undertaken within the First 2 Years of Life. Ophthalmology. 2015 Nov;122(11):2216-22. doi: 10.1016/j.ophtha.2015.07.028[↩]
122. Khaw PT, Chiang M, Shah P, Sii F, Lockwood A, Khalili A. Enhanced trabeculectomy: the Moorfields Safer Surgery System. Dev Ophthalmol. 2012;50:1-28. doi: 10.1159/000334776[↩]
123. Low S, Hamada S, Nischal KK. Antimetabolite and releasable suture augmented filtration surgery in refractory pediatric glaucomas. J AAPOS. 2008 Apr;12(2):166-72. doi: 10.1016/j.jaapos.2007.09.012[↩]
124. Beck AD, Wilson WR, Lynch MG, Lynn MJ, Noe R. Trabeculectomy with adjunctive mitomycin C in pediatric glaucoma. Am J Ophthalmol. 1998 Nov;126(5):648-57. doi: 10.1016/s0002-9394(98)00227-x[↩]
125. Margeta MA, Kuo AN, Proia AD, Freedman SF. Staying away from the optic nerve: a formula for modifying glaucoma drainage device surgery in pediatric and other small eyes. J AAPOS. 2017 Feb;21(1):39-43.e1. doi: 10.1016/j.jaapos.2016.09.027[↩]
126. Ishida K, Mandal AK, Netland PA. Glaucoma drainage implants in pediatric patients. Ophthalmol Clin North Am. 2005 Sep;18(3):431-42, vii. doi: 10.1016/j.ohc.2005.05.009[↩]
127. Tung I, Marcus I, Thiamthat W, Freedman SF. Second glaucoma drainage devices in refractory pediatric glaucoma: failure by fibrovascular ingrowth. Am J Ophthalmol. 2014 Jul;158(1):113-7. doi: 10.1016/j.ajo.2014.03.017[↩]
128. Cunliffe IA, Molteno AC. Long-term follow-up of Molteno drains used in the treatment of glaucoma presenting in childhood. Eye (Lond). 1998;12 ( Pt 3a):379-85. doi: 10.1038/eye.1998.90[↩]
129. Beck AD, Freedman S, Kammer J, Jin J. Aqueous shunt devices compared with trabeculectomy with Mitomycin-C for children in the first two years of life. Am J Ophthalmol. 2003 Dec;136(6):994-1000. doi: 10.1016/s0002-9394(03)00714-1[↩]
130. Tai AX, Song JC. Surgical outcomes of Baerveldt implants in pediatric glaucoma patients. J AAPOS. 2014 Dec;18(6):550-3. doi: 10.1016/j.jaapos.2014.08.003[↩]
131. Mandalos A, Tailor R, Parmar T, Sung V. The Long-term Outcomes of Glaucoma Drainage Device in Pediatric Glaucoma. J Glaucoma. 2016 Mar;25(3):e189-95. doi: 10.1097/IJG.0000000000000164[↩]
132. Razeghinejad MR, Kaffashan S, Nowroozzadeh MH. Results of Ahmed glaucoma valve implantation in primary congenital glaucoma. J AAPOS. 2014 Dec;18(6):590-5. doi: 10.1016/j.jaapos.2014.08.008[↩]
133. Pakravan M, Esfandiari H, Yazdani S, Doozandeh A, Dastborhan Z, Gerami E, Kheiri B, Pakravan P, Yaseri M, Hassanpour K. Clinical outcomes of Ahmed glaucoma valve implantation in pediatric glaucoma. Eur J Ophthalmol. 2019 Jan;29(1):44-51. doi: 10.1177/1120672118761332[↩]
134. Abdelrahman AM, El Sayed YM. Micropulse Versus Continuous Wave Transscleral Cyclophotocoagulation in Refractory Pediatric Glaucoma. J Glaucoma. 2018 Oct;27(10):900-905. doi: 10.1097/IJG.0000000000001053[↩]
135. Way AL, Nischal KK. High-frequency ultrasound-guided transscleral diode laser cyclophotocoagulation. Br J Ophthalmol. 2014 Jul;98(7):992-4. doi: 10.1136/bjophthalmol-2014-305163[↩]
136. Bock CJ, Freedman SF, Buckley EG, Shields MB. Transscleral diode laser cyclophotocoagulation for refractory pediatric glaucomas. J Pediatr Ophthalmol Strabismus. 1997 Jul-Aug;34(4):235-9. doi: 10.3928/0191-3913-19970701-11[↩]
137. Kirwan JF, Shah P, Khaw PT. Diode laser cyclophotocoagulation: role in the management of refractory pediatric glaucomas. Ophthalmology. 2002 Feb;109(2):316-23. doi: 10.1016/s0161-6420(01)00898-3[↩]
138. Autrata R, Rehurek J. Long-term results of transscleral cyclophotocoagulation in refractory pediatric glaucoma patients. Ophthalmologica. 2003 Nov-Dec;217(6):393-400. doi: 10.1159/000073068[↩]
139. Sood S, Beck AD. Cyclophotocoagulation versus sequential tube shunt as a secondary intervention following primary tube shunt failure in pediatric glaucoma. J AAPOS. 2009 Aug;13(4):379-83. doi: 10.1016/j.jaapos.2009.05.006[↩]
140. Neely DE, Plager DA. Endocyclophotocoagulation for management of difficult pediatric glaucomas. J AAPOS. 2001 Aug;5(4):221-9. doi: 10.1067/mpa.2001.116868[↩]
141. Glaser TS, Mulvihill MS, Freedman SF. Endoscopic cyclophotocoagulation (ECP) for childhood glaucoma: a large single-center cohort experience. J AAPOS. 2019 Apr;23(2):84.e1-84.e7. doi: 10.1016/j.jaapos.2018.10.014[↩]
142. Christy J, Jain N, Gurnani B, Kaur K. Twinkling Eye -A Rare Presentation in Neovascular Glaucoma. J Glaucoma. 2019 May 23. doi: 10.1097/IJG.0000000000001287[↩]
143. Gurnani B, Kaur K, Sekaran S. First case of coloboma, lens neovascularization, traumatic cataract, and retinal detachment in a young Asian female. Clin Case Rep. 2021 Aug 30;9(9):e04743. doi: 10.1002/ccr3.4743[↩]
144. Gurnani B, Kaur K, Gireesh P. A rare presentation of anterior dislocation of calcified capsular bag in a spontaneously absorbed cataractous eye. Oman J Ophthalmol. 2021 Jun 28;14(2):120-121. doi: 10.4103/ojo.OJO_65_2019[↩]
145. Gurnani B, Kaur K, Gireesh P. Rare Coexistence of Bilateral Congenital Sutural and Cortical Blue Dot Cataracts. J Pediatr Ophthalmol Strabismus. 2020 Jan 1;57(1):68. doi: 10.3928/01913913-20191011-01[↩]
146. Kaur K, Gurnani B, Kannusamy V, Yadalla D. A tale of orbital cellulitis and retinopathy of prematurity in an infant: First case report. Eur J Ophthalmol. 2022 Nov;32(6):NP20-NP23. doi: 10.1177/11206721211026098[↩]
147. Baig NB, Lin AA, Freedman SF. Ultrasound evaluation of glaucoma drainage devices in children. J AAPOS. 2015 Jun;19(3):281-4. doi: 10.1016/j.jaapos.2015.02.001[↩]
148. Neustein RF, Bruce BB, Beck AD. Primary Congenital Glaucoma Versus Glaucoma Following Congenital Cataract Surgery: Comparative Clinical Features and Long-term Outcomes. Am J Ophthalmol. 2016 Oct;170:214-222. doi: 10.1016/j.ajo.2016.08.012[↩]
149. Biglan AW, Hiles DA. The visual results following infantile glaucoma surgery. J Pediatr Ophthalmol Strabismus. 1979 Nov-Dec;16(6):377-81. doi: 10.3928/0191-3913-19791101-10[↩]
150. de Silva DJ, Khaw PT, Brookes JL. Long-term outcome of primary congenital glaucoma. J AAPOS. 2011 Apr;15(2):148-52. doi: 10.1016/j.jaapos.2010.11.025[↩]
151. Shaffer RN. Prognosis of goniotomy in primary infantile glaucoma (trabeculodysgenesis). Trans Am Ophthalmol Soc. 1982;80:321-5. https://pmc.ncbi.nlm.nih.gov/articles/instance/1312272/pdf/taos00019-0346.pdf[↩]
152. Kantipuly A, Pillai MR, Shroff S, Khatiwala R, Raman GV, Krishnadas SR, Lee Robin A, Ehrlich JR. Caregiver Burden in Primary Congenital Glaucoma. Am J Ophthalmol. 2019 Sep;205:106-114. doi: 10.1016/j.ajo.2019.05.003[↩]
153. McLaughlin DE, Semrov A, Munshi H, Patel AJ, Rahi J, Grajewski AL; Balkan CGRN Study Group. The impact of childhood glaucoma on psychosocial functioning and quality of life: a review of the literature. Eye (Lond). 2023 Oct;37(15):3157-3173. doi: 10.1038/s41433-023-02492-1[↩]

Stahl’s ear

Stahl’s ear deformity consists of an extra cartilage fold in the middle (scapha) portion of the ear. This results in a pointy ear shape. Stahl’s ear is a defect that babies are born with.

If Stahl’s ear is treated very early in life (first 8 weeks of life), it can be corrected with the use of a mold that the patient wears for a couple of months. In older children, molding is not as effective. Surgical correction of a Stahl’s ear deformity is then required. This is typically performed when the child is around 7-10 years old.

Figure 1. Stahl’s ear deformity (before and after ear moulding)

Stahl’s ear cause

Stahl’s ear is caused by misshapen cartilage. But the exact reason that this occurs is unclear. Stahl’s ear is characterized by an extra horizontal fold of cartilage (crus). Normally, there are two: superior and inferior. In Stahl’s ear, there is a third horizontal crus. The helix (or upper portion of the ear) may uncurl, giving the ear a pointed shape.

What are the symptoms of Stahl’s ear?

Other than the physical appearance of the ear, there are no other symptoms associated with Stahl’s ear. Affected children usually have normal hearing.

Stahl’s ear treatment

If Stahl’s ear is discovered in the first few weeks to months after birth, ear molding may correct this deformity and avoid the need for surgery. Infants’ ears are still soft and flexible, which makes them responsive to molding. Like many other conditions in which ear molding is useful (such as cryptotia, constricted ears and protruding ears), the earlier the intervention, the shorter the treatment. Early treatment also often leads to better outcomes.

In older children, surgical correction is necessary to correct the deformity. Surgery to correct Stahl’s ear involves reshaping, repositioning and suturing the abnormal cartilage to reverse the pointed shape of the ear. Although a general anesthetic is needed, the operation is done on an outpatient basis and your child will be able to return home the same day.

How best to properly clean your ears

Earwax is inevitable and as you grow older, problematic buildups of earwax become more common. Left unchecked, these can lead to hearing loss.

But, good intentions to keep your ears clean may weaken your ability to hear. The ear is a delicate and intricate body part, including the skin of the ear canal and the eardrum. Therefore, special care should be given to this part of the body. Start by discontinuing the habit of inserting cotton-tipped applicators or other objects into the ear canals.

What is Earwax ?

Earwax or cerumen is healthy in normal amounts and serves as a self-cleaning agent with protective, lubricating, and antibacterial properties ¹. The absence of earwax may result in dry, itchy ears. Self-cleaning means there is a slow and orderly movement of earwax and dead skin cells from the eardrum to the ear opening. Old earwax is constantly being transported, assisted by chewing and jaw motion, from the ear canal to the ear opening where, most of the time, it dries, flakes, and falls out. And you shouldn’t need to do anything to keep your ears clean of wax ¹.

Earwax is not formed in the deep part of the ear canal near the eardrum. It is only formed in the outer one-third of the ear canal. So, when you have a wax blocking against the eardrum, it is often because you have been probing the ear with such things as cotton-tipped applicators, bobby pins, or twisted napkin corners. These objects only push the wax in deeper.

Figure 1. Ear anatomy

When should the ears be cleaned ?

Under ideal circumstances, the ear canals should never have to be cleaned. However, that isn’t always the case. The ears should be cleaned when enough earwax accumulates to cause symptoms or to prevent a needed assessment of the ear by your doctor. This condition is call cerumen impaction and may cause one or more of the following symptoms:

• Earache, fullness in the ear, or a sensation the ear is plugged
• Partial hearing loss, which may be progressive
• Tinnitus, ringing, or noises in the ear
• Itching, odor, or discharge
• Coughing

What is the recommended method of ear cleaning ?

To clean the ears, wash the external ear with a cloth, but do not insert anything into the ear canal.

Most cases of ear wax blockage respond to home treatments used to soften wax. You can try placing a few drops of mineral oil, baby oil, glycerin, or commercial drops in the ear. Detergent drops such as hydrogen peroxide or carbamide peroxide (available in most pharmacies) may also aid in the removal of wax.

Irrigation or ear syringing is commonly used for cleaning and can be performed by a physician or at home using a commercially available irrigation kit. Common solutions used for syringing include water and saline, which should be warmed to body temperature to prevent dizziness. Ear syringing is most effective when water, saline, or wax dissolving drops are put in the ear canal 15 to 30 minutes before treatment. Caution is advised to avoid having your ears irrigated if you have diabetes, a hole in the eardrum (perforation), tube in the eardrum, skin problems such as eczema in the ear canal or a weakened immune system.

Manual removal of earwax is also effective. This is most often performed by an otolaryngologist (ear doctor specialist) using suction or special miniature instruments, and a microscope to magnify the ear canal. Manual removal is preferred if your ear canal is narrow, the eardrum has a perforation or tube, other methods have failed, or if you have skin problems affecting the ear canal, diabetes or a weakened immune system.

Are ear candles an option for removing wax build up ?

No, ear candles are not a safe option of wax removal as they may result in serious injury. Since users are instructed to insert the 10- to 15-inch-long, cone-shaped, hollow candles, typically made of wax-impregnated cloth, into the ear canal and light the exposed end, some of the most common injuries are burns, obstruction of the ear canal with wax of the candle, or perforation of the membrane that separates the ear canal and the middle ear.

The U.S. Food and Drug Administration (FDA) became concerned about the safety issues with ear candles after receiving reports of patient injury caused by the ear candling procedure. There are no controlled studies or other scientific evidence that support the safety and effectiveness of these devices for any of the purported claims or intended uses as contained in the labeling.

Based on the growing concern associated with the manufacture, marketing, and use of ear candles, the FDA has undertaken several successful regulatory actions, including product seizures and injunctions, since 1996. These actions were based, in part, upon violations of the Food, Drug, and Cosmetic Act that pose an imminent danger to health.

When should a doctor be consulted ?

If the home treatments discussed in this leaflet are not satisfactory or if wax has accumulated so much that it blocks the ear canal (and hearing), a physician may prescribe eardrops designed to soften wax, or she may wash or vacuum it out. Occasionally, an otolaryngologist (ear, nose, and throat specialist) may need to remove the wax under microscopic visualization.

If there is a possibility of a perforation in the eardrum, consult a physician prior to trying any over-the-counter remedies. Putting eardrops or other products in the ear with the presence of an eardrum perforation may cause pain or an infection. Certainly, washing water through such a hole could start an infection.

What can I do to prevent excessive earwax ?

There are no proven ways to prevent cerumen impaction, but not inserting cotton-tipped swabs or other objects in the ear canal is strongly advised. If you are prone to repeated wax impaction or use hearing aids, consider seeing your doctor every 6 to 12 months for a checkup and routine preventive cleaning.

1. Earwax and Care. http://www.entnet.org/content/earwax-and-care[↩][↩]

Human ear

The ear is divided into three anatomical regions: the external ear, the middle ear, and the internal ear (Figure 2). The external ear is the visible portion of the ear, and it collects and directs sound waves to the eardrum. The middle ear is a chamber located within the petrous portion of the temporal bone. Structures within the middle ear amplify sound waves and transmit them to an appropriate portion of the internal ear. The internal ear contains the sensory organs for equilibrium (balance) and hearing.

Figure 1. Ear structure

Figure 2. Ear anatomy

Parts of the ear

External (Outer) Ear

The external (outer) ear consists of the auricle, external auditory canal, and eardrum (Figure 1 and 2). The auricle or pinna is a flap of elastic cartilage shaped like the flared end of a trumpet and covered by skin. The rim of the auricle is the helix; the inferior portion is the lobule. Ligaments and muscles attach the auricle to the head. The external auditory canal is a curved tube about 2.5 cm (1 in.) long that lies in the temporal bone and leads to the eardrum.

The tympanic membrane or ear drum is a thin, semitransparent partition between the external auditory canal and middle ear. The tympanic membrane is covered by epidermis and lined by simple cuboidal epithelium. Between the epithelial layers is connective tissue composed of collagen, elastic fibers, and fibroblasts. Tearing of the tympanic membrane is called a perforated eardrum. It may be due to pressure from a cotton swab, trauma, or a middle ear infection, and usually heals within a month. The tympanic membrane may be examined directly by an otoscope, a viewing instrument that illuminates and magnifies the external auditory canal and tympanic membrane.

Near the exterior opening, the external auditory canal contains a few hairs and specialized sweat glands called ceruminous glands that secrete earwax or cerumen. The combination of hairs and cerumen helps prevent dust and foreign objects from entering the ear. Cerumen also prevents damage to the delicate skin of the external ear canal by water and insects. Cerumen usually dries up and falls out of the ear canal. However, some people produce a large amount of cerumen, which can become impacted and can muffle incoming sounds. The treatment for impacted cerumen is usually periodic ear irrigation or removal of wax with a blunt instrument by trained medical personnel.

Middle Ear

The middle ear is a small, air-filled cavity in the petrous portion of the temporal bone that is lined by epithelium. It is separated from the external ear by the tympanic membrane and from the internal ear by a thin bony partition that contains two small openings: the oval window and the round window.

Extending across the middle ear and attached to it by ligaments are the three smallest bones in the body, the auditory ossicles, which are connected by synovial joints. The bones, named for their shapes, are the malleus, incus, and stapes—commonly called the hammer, anvil, and stirrup, respectively. The “handle” of the malleus attaches to the internal surface of the tympanic membrane. The head of the malleus articulates with the body of the incus. The incus, the middle bone in the series, articulates with the head of the stapes. The base or footplate of the stapes fits into the oval window. Directly below the oval window is another opening, the round window, which is enclosed by a membrane called the secondary tympanic membrane. Besides the ligaments, two tiny skeletal muscles also attach to the ossicles (Figure 3).

Figure 3. Middle ear and auditory ossicles

The tensor tympani muscle, which is supplied by the mandibular branch of the trigeminal (V) nerve, limits movement and increases tension on the eardrum to prevent damage to the inner ear from loud noises. The stapedius muscle, which is supplied by the facial (VII) nerve, is the smallest skeletal muscle in the human body. By dampening large vibrations of the stapes due to loud noises, it protects the oval window, but it also decreases the sensitivity of hearing. For this reason, paralysis of the stapedius muscle is associated with hyperacusia, which is abnormally sensitive hearing. Because it takes a fraction of a second for the tensor tympani and stapedius muscles to contract, they can protect the inner ear from prolonged loud noises but not from brief ones such as a gunshot.

The anterior wall of the middle ear contains an opening that leads directly into the auditory tube or pharyngotympanic tube, commonly known as the eustachian tube. The auditory tube, which consists of both bone and elastic cartilage, connects the middle ear with the nasopharynx (superior portion of the throat). It is normally closed at its medial (pharyngeal) end. During swallowing and yawning, it opens, allowing air to enter or leave the middle ear until the pressure in the middle ear equals the atmospheric pressure. Most of us have experienced our ears popping as the pressures equalize. When the pressures are balanced, the tympanic membrane vibrates freely as sound waves strike it. If the pressure is not equalized, intense pain, hearing impairment, ringing in the ears, and vertigo could develop. The auditory tube also is a route for pathogens to travel from the nose and throat to the middle ear, causing the most common type of ear infection.

Internal (Inner)

Ear The internal (inner) ear is also called the labyrinth because of its complicated series of canals (Figure 4, 5 and 6). Structurally, it consists of two main divisions: an outer bony labyrinth that encloses an inner membranous labyrinth. It is like long balloons put inside a rigid tube. The bony labyrinth is a series of cavities in the petrous portion of the temporal bone divided into three areas: (1) the semicircular canals, (2) the vestibule, and (3) the cochlea.

Figure 4. Parts of the inner ear

The bony labyrinth is lined with periosteum and contains perilymph. This fluid, which is chemically similar to cerebrospinal fluid, surrounds the membranous labyrinth, a series of epithelial sacs and tubes inside the bony labyrinth that have the same general form as the bony labyrinth and house the receptors for hearing and equilibrium. The epithelial membranous labyrinth contains endolymph. The level of potassium ions (K+) in endolymph is unusually high for an extracellular fluid, and potassium ions play a role in the generation of auditory signals.

The vestibule is the oval central portion of the bony labyrinth. The membranous labyrinth in the vestibule consists of two sacs called the utricle (little bag) and the saccule (little sac), which are connected by a small duct. Projecting superiorly and posteriorly from the vestibule are the three bony semicircular canals, each of which lies at approximately right angles to the other two. Based on their positions, they are named the anterior, posterior, and lateral semicircular canals. The anterior and posterior semicircular canals are vertically oriented; the lateral one is horizontally oriented. At one end of each canal is a swollen enlargement called the ampulla. The portions of the membranous labyrinth that lie inside the bony semicircular canals are called the semicircular ducts. These structures connect with the utricle of the vestibule.

The vestibular branch of the vestibulocochlear (cranial nerve VIII) nerve consists of ampullary, utricular, and saccular nerves. These nerves contain both first-order sensory neurons and efferent neurons that synapse with receptors for equilibrium. The first-order sensory neurons carry sensory information from the receptors, and the efferent neurons carry feedback signals to the receptors, apparently to modify their sensitivity. Cell bodies of the sensory neurons are located in the vestibular ganglia.

Figure 5. Inner ear bones

Note: A closer look at the inner ear. Perilymph separates the bony (osseous) labyrinth of the inner ear from the membranous labyrinth, which contains endolymph. Note that areas of bony labyrinth have been removed to reveal underlying structures.

Figure 6. The Cochlea (cross section view)

Note: a) Cross section of the cochlea. (b) The spiral organ and the tectorial membrane.

Anterior to the vestibule is the cochlea, a bony spiral canal that resembles a snail’s shell and makes almost three turns around a central bony core called the modiolus. Sections through the cochlea reveal that it is divided into three channels: cochlear duct, scala vestibuli, and scala tympani. The cochlear duct or scala media is a continuation of the membranous labyrinth into the cochlea; it is filled with endolymph. The channel above the cochlear duct is the scala vestibuli, which ends at the oval window. The channel below is the scala tympani, which ends at the round window. Both the scala vestibuli and scala tympani are part of the bony labyrinth of the cochlea; therefore, these chambers are filled with perilymph. The scala vestibuli and scala tympani are completely separated by the cochlear duct, except for an opening at the apex of the cochlea, the helicotrema.

The cochlea adjoins the wall of the vestibule, into which the scala vestibuli opens. The perilymph in the vestibule is continuous with that of the scala vestibuli. The vestibular membrane separates the cochlear duct from the scala vestibuli, and the basilar membrane separates the cochlear duct from the scala tympani. Resting on the basilar membrane is the spiral organ or organ of Corti. The spiral organ is a coiled sheet of epithelial cells, including supporting cells and about 16,000 hair cells, which are the receptors for hearing.

There are two groups of hair cells: The inner hair cells are arranged in a single row, whereas the outer hair cells are arranged in three rows. At the apical tip of each hair cell are stereocilia that extend into the endolymph of the cochlear duct. Despite their name, stereocilia are actually long, hairlike microvilli arranged in several rows of graded height.

At their basal ends, inner and outer hair cells synapse both with first-order sensory neurons and with motor neurons from the cochlear branch of the vestibulocochlear (VIII) nerve. Cell bodies of the sensory neurons are located in the spiral ganglion. Although outer hair cells outnumber them by 3 to 1, the inner hair cells synapse with 90–95% of the first-order sensory neurons in the cochlear nerve that relay auditory information to the brain. By contrast, 90% of the motor neurons in the cochlear nerve synapse with outer hair cells. The tectorial membrane, a flexible gelatinous membrane, covers the hair cells of the spiral organ. In fact, the ends of the stereocilia of the hair cells are embedded in the tectorial membrane while the bodies of the hair cells rest on the basilar membrane. Inner and outer hair cells have diff erent functional roles. Inner hair cells are the receptors for hearing: They convert the mechanical vibrations of sound into  electrical signals. Outer hair cells do not serve as hearing receptors; instead, they increase the sensitivity of the inner hair cells.

Mechanism for Hearing

First, sound vibrations travel from the eardrum through the ossicles, causing the stapes to oscillate back and forth against the oval window. This oscillation sets up pressure waves in the perilymph of the scala vestibuli, which are transferred to the endolymph of the cochlear duct. These waves cause the basilar membrane to vibrate up and down. The hair cells in the spiral organ move along with the basilar membrane, but the overlying tectorial membrane (in which the hairs are anchored) does not move. Therefore, the movements of the hair cells cause their hairs to bend. Each time such bending occurs in a specific direction, the hair cells release neurotransmitters that excite the cochlear nerve fibers, which carry the vibratory (sound) information to the brain. The vibrations of the basilar membrane set the perilymph vibrating in the underlying scala tympani. These vibrations then travel to the round window, where they push on the membrane that covers that window, thereby dissipating their remaining energy into the air of the middle ear cavity. Without this release mechanism, echoes would reverberate within the rigid cochlear box, disrupting sound reception.

The inner and outer hair cells in the spiral organ have different functions. The inner hair cells are the true receptors that transmit the vibrations of the basilar membrane to the cochlear nerve. The outer hair cells are involved with actively tuning the cochlea and amplifying the signal. The outer hair cells receive efferent fibers from the brain that cause these cells to stretch and contract, enhancing the responsiveness of the inner hair cell receptors. Overall, this active mechanism amplifies sounds some 100 times, so that we can hear the faintest sounds.The mobility of the outer hair cells is also responsible for producing ear sounds (otoacoustic emissions). Detection of spontaneous otoacoustic emissions is used to test hearing in newborns.

Ear problems

Swimmer’s ear

Swimmer’s ear is an infection in the outer ear canal, which runs from your eardrum to the outside of your head ¹. It’s often brought on by water that remains in your ear after swimming, creating a moist environment that aids bacterial growth.

Putting fingers, cotton swabs or other objects in your ears also can lead to swimmer’s ear by damaging the thin layer of skin lining your ear canal ¹.

Swimmer’s ear is also known as otitis externa. The most common cause of this infection is bacteria invading the skin inside your ear canal. Usually you can treat swimmer’s ear with eardrops. Prompt treatment can help prevent complications and more-serious infections.

Causes of Swimmer’s ear

Swimmer’s ear is an infection that’s usually caused by bacteria commonly found in water and soil. Infections caused by a fungus or a virus are less common. Swimmer’s ear is more common among children in their teens and young adults. It may occur with a middle ear infection or a respiratory infection such as a cold.

Swimming in unclean water can lead to swimmer’s ear. Bacteria commonly often found in water can cause ear infections. Rarely, the infection may be caused by a fungus.

Other causes of swimmer’s ear include:

• Scratching the ear or inside the ear
• Getting something stuck in the ear

Trying to clean (wax from the ear canal) with cotton swabs or small objects can damage the skin.

Long-term (chronic) swimmer’s ear may be due to:

• Allergic reaction to something placed in the ear
• Chronic skin conditions, such as eczema or psoriasis

Your ear’s natural defenses

Your outer ear canals have natural defenses that help keep them clean and prevent infection. Protective features include:

• Glands that secrete a waxy substance (cerumen). These secretions form a thin, water-repellent film on the skin inside your ear. Cerumen is also slightly acidic, which helps further discourage bacterial growth. In addition, cerumen collects dirt, dead skin cells and other debris and helps move these particles out of your ear. The waxy clump that results is the familiar earwax you find at the opening of your ear canal.

• Downward slope of your ear canal. Your ear canal slopes down slightly from your middle ear to your outer ear, helping water drain out.

How the swimmer’s ear occurs

If you have swimmer’s ear, your natural defenses have been overwhelmed. Conditions that can weaken your ear’s defenses and promote bacterial growth include:

• Excess moisture in your ear. Heavy perspiration, prolonged humid weather or water that remains in your ear after swimming can create a favorable environment for bacteria.
• Scratches or abrasions in your ear canal. Cleaning your ear with a cotton swab or hairpin, scratching inside your ear with a finger, or wearing headphones or hearing aids can cause small breaks in the skin that allow bacteria to grow.
• Sensitivity reactions. Hair products or jewelry can cause allergies and skin conditions that promote infection.

Risk factors for swimmer’s ear

Factors that may increase your risk of swimmer’s ear include:

• Swimming
• Swimming in water with elevated bacteria levels, such as a lake rather than a well-maintained pool
• A narrow ear canal — for example, in a child — that can more easily trap water
• Aggressive cleaning of the ear canal with cotton swabs or other objects
• Use of certain devices, such as headphones or a hearing aid
• Skin allergies or irritation from jewelry, hair spray or hair dyes

Symptoms of Swimmer’s ear

Swimmer’s ear symptoms are usually mild at first, but they may get worse if your infection isn’t treated or spreads. Doctors often classify swimmer’s ear according to mild, moderate and advanced stages of progression.

Mild signs and symptoms

• Itching in your ear canal
• Slight redness inside your ear
• Mild discomfort that’s made worse by pulling on your outer ear (pinna, or auricle) or pushing on the little “bump” (tragus) in front of your ear
• Some drainage of clear, odorless fluid

Moderate progression

• More intense itching
• Increasing pain
• More extensive redness in your ear
• Excessive fluid drainage
• Discharge of pus
• Feeling of fullness inside your ear and partial blockage of your ear canal by swelling, fluid and debris
• Decreased or muffled hearing

Advanced progression

• Severe pain that may radiate to your face, neck or side of your head
• Complete blockage of your ear canal
• Redness or swelling of your outer ear
• Swelling in the lymph nodes in your neck
• Fever

When to see a doctor

See your doctor if you’re experiencing any signs or symptoms of swimmer’s ear, even if they’re mild.

Call your doctor immediately or visit the emergency room if you have:

• Severe pain
• Fever

Complications of Swimmer’s ear

Swimmer’s ear usually isn’t serious if treated promptly, but complications can occur.

• Temporary hearing loss. You may experience muffled hearing that usually gets better after the infection clears up.
• Long-term infection (chronic otitis externa). An outer ear infection is usually considered chronic if signs and symptoms persist for more than three months.
• Chronic infections are more common if there are conditions that make treatment difficult, such as a rare strain of bacteria, an allergic skin reaction, an allergic reaction to antibiotic eardrops, or a combination of a bacterial and fungal infection.
• Deep tissue infection (cellulitis). Rarely, swimmer’s ear may result in the spread of infection into deep layers and connective tissues of the skin.
• Bone and cartilage damage (necrotizing otitis externa). An outer ear infection that spreads can cause inflammation and damage to the skin and cartilage of the outer ear and bones of the lower part of the skull, causing increasingly severe pain. Older adults, people with diabetes or people with weakened immune systems are at increased risk of this complication. Necrotizing otitis externa is also known as malignant otitis externa, but it’s not a cancer.
• More widespread infection. If swimmer’s ear develops into necrotizing otitis externa, the infection may spread and affect other parts of your body, such as the brain or nearby nerves. This rare complication can be life-threatening.

Prevention of Swimmer’s ear

Follow these tips to avoid swimmer’s ear:

• Keep your ears dry. Dry your ears thoroughly after exposure to moisture from swimming or bathing. Dry only your outer ear, wiping it slowly and gently with a soft towel or cloth. Tip your head to the side to help water drain from your ear canal. You can dry your ears with a blow dryer if you put it on the lowest setting and hold it at least a foot (about 0.3 meters) away from the ear.
• At-home preventive treatment. If you know you don’t have a punctured eardrum, you can use homemade preventive eardrops before and after swimming. A mixture of 1 part white vinegar to 1 part rubbing alcohol may help promote drying and prevent the growth of bacteria and fungi that can cause swimmer’s ear. Pour 1 teaspoon (about 5 milliliters) of the solution into each ear and let it drain back out. Similar over-the-counter solutions may be available at your drugstore.
• Swim wisely. Watch for signs alerting swimmers to high bacterial counts and don’t swim on those days.
• DO NOT scratch the ears or insert cotton swabs or other objects in the ears.
• Avoid putting foreign objects in your ear. Never attempt to scratch an itch or dig out earwax with items such as a cotton swab, paper clip or hairpin. Using these items can pack material deeper into your ear canal, irritate the thin skin inside your ear or break the skin.
• Protect your ears from irritants. Put cotton balls in your ears while applying products such as hair sprays and hair dyes.
• Use caution after an ear infection or surgery. If you’ve recently had an ear infection or ear surgery, talk to your doctor before you go swimming.

Diagnosis of swimmer’s ear

Doctors can usually diagnose swimmer’s ear during an office visit. If your infection is at an advanced stage or persists, you may need further evaluation.
Initial testing

Your doctor will likely diagnose swimmer’s ear based on symptoms you report, questions he or she asks, and an office examination. You probably won’t need a lab test at your first visit. Your doctor’s initial evaluation will usually include:

• Examination of your ear canal with a lighted instrument (otoscope). Your ear canal may appear red, swollen and scaly. Flakes of skin and other debris may be present in the ear canal.
• Visualization of your eardrum (tympanic membrane) to be sure it isn’t torn or damaged. If the view of your eardrum is blocked, your doctor will clear your ear canal with a small suction device or an instrument with a tiny loop or scoop on the end (ear curette).

Further testing

Depending on the initial assessment, symptom severity or the stage of your swimmer’s ear, your doctor may recommend additional evaluation.

• If your eardrum is damaged or torn, your doctor will likely refer you to an ear, nose and throat specialist (ENT). The specialist will examine the condition of your middle ear to determine if that’s the primary site of infection. This examination is important because some treatments intended for an infection in the outer ear canal aren’t appropriate for treating the middle ear.

• If your infection doesn’t respond to treatment, your doctor may take a sample of discharge or debris from your ear at a later appointment and send it to a lab to identify the exact microorganism causing your infection.

Treatment for swimmer’s ear

The goal of treatment is to stop the infection and allow your ear canal to heal.

Cleaning

Cleaning your outer ear canal is necessary to help eardrops flow to all infected areas. Your doctor will use a suction device or ear curette to clean away any discharge, clumps of earwax, flaky skin and other debris.

Medications for infection

For most cases of swimmer’s ear, your doctor will prescribe eardrops that have some combination of the following ingredients, depending on the type and seriousness of your infection:

• Acidic solution to help restore your ear’s normal antibacterial environment
• Steroid to reduce inflammation
• Antibiotic to fight bacteria
• Antifungal medication to fight an infection caused by a fungus

Ask your doctor about the best method for taking your eardrops. Some ideas that may help you use eardrops include the following:

• Reduce the discomfort of cool drops by holding the bottle in your hand for a few minutes to bring the temperature of the drops closer to body temperature.
• Lie on your side with your infected ear up for a few minutes to help medication travel through the full length of your ear canal.
• If possible, have someone help you put the drops in your ear.

If your ear canal is completely blocked by swelling, inflammation or excess discharge, your doctor may insert a wick made of cotton or gauze to promote drainage and help draw medication into your ear canal.

If your infection is more advanced or doesn’t respond to treatment with eardrops, your doctor may prescribe oral antibiotics.

Medications for pain

Your doctor may recommend easing the discomfort of swimmer’s ear with over-the-counter pain relievers, such as ibuprofen (Advil, Motrin IB, others), naproxen sodium (Aleve, others) or acetaminophen (Tylenol, others).

If your pain is severe or your swimmer’s ear is at a more advanced stage, your doctor may prescribe a stronger medication for pain relief.

Helping your treatment work

During treatment, the following steps will help keep your ears dry and avoid further irritation:

• Don’t swim or scuba dive.
• Avoid flying.
• Don’t wear an earplug, hearing aid or headphones before pain or discharge has stopped.
• Avoid getting water in your ear canal when bathing. Use a cotton ball coated with petroleum jelly to protect your ear during a bath.

Ruptured eardrum (perforated eardrum)

A ruptured eardrum — or tympanic membrane perforation as it’s medically known — is a hole or tear in the thin tissue that separates your ear canal from your middle ear (eardrum) ².

A ruptured eardrum can result in hearing loss. A ruptured eardrum can also make your middle ear vulnerable to infections or injury.

A ruptured eardrum usually heals within a few weeks without treatment. Sometimes, however, a ruptured eardrum requires a procedure or surgical repair to heal.

If you think that you have a ruptured eardrum, be careful to keep your ears dry to prevent infection. Don’t go swimming. To keep water out of your ear when showering or bathing, use a moldable, waterproof silicone earplug or put a cotton ball coated with petroleum jelly in your outer ear.

Don’t put medication drops in your ear unless your doctor prescribes them specifically for infection related to your perforated eardrum.

Causes of a ruptured or perforated eardrum

Causes of a ruptured, or perforated, eardrum may include:

• Middle ear infection (otitis media). A middle ear infection often results in the accumulation of fluids in your middle ear. Pressure from these fluids can cause the eardrum to rupture.
• Barotrauma. Barotrauma is stress exerted on your eardrum when the air pressure in your middle ear and the air pressure in the environment are out of balance. If the pressure is severe, your eardrum can rupture. Barotrauma is most often caused by air pressure changes associated with air travel.
• Other events that can cause sudden changes in pressure — and possibly a ruptured eardrum — include scuba diving and a direct blow to the ear, such as the impact of an automobile air bag.
• Loud sounds or blasts (acoustic trauma). A loud sound or blast, as from an explosion or gunshot — essentially an overpowering sound wave — can cause a tear in your eardrum.
• Foreign objects in your ear. Small objects, such as a cotton swab or hairpin, can puncture or tear the eardrum.
• Severe head trauma. Severe injury, such as skull fracture, may cause the dislocation or damage to middle and inner ear structures, including your eardrum.

Complications of of a ruptured or perforated eardrum

Your eardrum (tympanic membrane) has two primary roles:

• Hearing. When sound waves strike it, your eardrum vibrates — the first step by which structures of your middle and inner ears translate sound waves into nerve impulses.
• Protection. Your eardrum also acts as a barrier, protecting your middle ear from water, bacteria and other foreign substances.

If your eardrum ruptures, complications can occur while your eardrum is healing or if it fails to heal. Possible complications include:

• Hearing loss. Usually, hearing loss is temporary, lasting only until the tear or hole in your eardrum has healed. The size and location of the tear can affect the degree of hearing loss.
• Middle ear infection (otitis media). A perforated eardrum can allow bacteria to enter your ear. If a perforated eardrum doesn’t heal or isn’t repaired, you may be vulnerable to ongoing (chronic) infections that can cause permanent hearing loss.
• Middle ear cyst (cholesteatoma). A cholesteatoma is a cyst in your middle ear composed of skin cells and other debris. Ear canal debris normally travels to your outer ear with the help of ear-protecting earwax. If your eardrum is ruptured, the skin debris can pass into your middle ear and form a cyst. A cholesteatoma provides a friendly environment for bacteria and contains proteins that can damage bones of your middle ear.

Prevention of a ruptured or perforated eardrum

Follow these tips to avoid a ruptured or perforated eardrum:

• Get treatment for middle ear infections. Be aware of the signs and symptoms of middle ear infection, including earache, fever, nasal congestion and reduced hearing. Children with a middle ear infection often rub or pull on their ears. Seek prompt evaluation from your primary care doctor to prevent potential damage to the eardrum.
• Protect your ears during flight. If possible, don’t fly if you have a cold or an active allergy that causes nasal or ear congestion. During takeoffs and landings, keep your ears clear with pressure-equalizing earplugs, yawning or chewing gum. Or use the Valsalva maneuver — gently blowing, as if blowing your nose, while pinching your nostrils and keeping your mouth closed. Don’t sleep during ascents and descents.
• Keep your ears free of foreign objects. Never attempt to dig out excess or hardened earwax with items such as a cotton swab, paper clip or hairpin. These items can easily tear or puncture your eardrum. Teach your children about the damage that can be done by putting foreign objects in their ears.
• Guard against excessive noise. Protect your ears from unnecessary damage by wearing protective earplugs or earmuffs in your workplace or during recreational activities if loud noise is present.

Symptoms of a ruptured or perforated eardrum

Signs and symptoms of a ruptured eardrum may include:

• Ear pain that may subside quickly
• Clear, pus-filled or bloody drainage from your ear
• Hearing loss
• Ringing in your ear (tinnitus)
• Spinning sensation (vertigo)
• Nausea or vomiting that can result from vertigo

When to see a doctor

Call your doctor if you experience any of the signs or symptoms of a ruptured eardrum or pain or discomfort in your ears. Your middle and inner ears are composed of delicate mechanisms that are sensitive to injury or disease. Prompt and appropriate treatment is important to preserve your hearing.

Diagnosis of a ruptured or perforated eardrum

Your family doctor or ENT specialist can often determine if you have a perforated eardrum with a visual inspection using a lighted instrument (otoscope).

He or she may conduct or order additional tests to determine the cause of the rupture or degree of damage. These tests include:

• Laboratory tests. If there’s discharge from your ear, your doctor may order a laboratory test or culture to detect a bacterial infection of your middle ear.
• Tuning fork evaluation. Tuning forks are two-pronged, metal instruments that produce sounds when struck. Simple tests with tuning forks can help your doctor detect hearing loss. A tuning fork evaluation may also reveal whether hearing loss is caused by damage to the vibrating parts of your middle ear (including your eardrum), damage to sensors or nerves of your inner ear, or damage to both.
• Tympanometry. A tympanometer uses a device inserted into your ear canal that measures the response of your eardrum to slight changes in air pressure. Certain patterns of response can indicate a perforated eardrum.
• Audiology exam. If other hearing tests are inconclusive, your doctor may order a series of strictly calibrated tests conducted in a soundproof booth that measure how well you hear sounds at different volumes and pitches (audiology exam).

Treatment of a ruptured or perforated eardrum

Most perforated eardrums heal without treatment within a few weeks. Your doctor may prescribe antibiotic drops if there’s evidence of infection. If the tear or hole in your eardrum doesn’t heal by itself, treatment will involve procedures to close the perforation. These may include:

• Eardrum patch. If the tear or hole in your eardrum doesn’t close on its own, an ENT specialist may seal it with a patch. With this office procedure, your ENT doctor may apply a chemical to the edges of the tear to stimulate growth and then apply a patch over the hole. The procedure may need to be repeated more than once before the hole closes.
• Surgery. If a patch doesn’t result in proper healing or your ENT doctor determines that the tear isn’t likely to heal with a patch, he or she may recommend surgery. The most common surgical procedure is called tympanoplasty. Your surgeon grafts a tiny patch of your own tissue to close the hole in the eardrum. This procedure is done on an outpatient basis, meaning you can usually go home the same day unless medical anesthesia conditions require a longer hospital stay.

Home remedies for a ruptured or perforated eardrum

A ruptured eardrum usually heals on its own within weeks. In some cases, healing takes months. Until your doctor tells you that your ear is healed, protect it by doing the following:

• Keep your ear dry. Place a waterproof silicone earplug or cotton ball coated with petroleum jelly in your ear when showering or bathing.
• Refrain from cleaning your ears. Give your eardrum time to heal completely.
• Avoid blowing your nose. The pressure created when blowing your nose can damage your healing eardrum.

Middle Ear Infection

An middle ear infection (acute otitis media) is most often a bacterial or viral infection that affects the middle ear, the air-filled space behind the eardrum that contains the tiny vibrating bones of the ear ³. Children are more likely than adults to get ear infections.

Ear infections frequently are painful because of inflammation and buildup of fluids in the middle ear.

Because ear infections often clear up on their own, treatment may begin with managing pain and monitoring the problem. Ear infection in infants and severe cases in general often require antibiotic medications. Long-term problems related to ear infections — persistent fluids in the middle ear, persistent infections or frequent infections — can cause hearing problems and other serious complications.

Symptoms of middle ear infection

The onset of signs and symptoms of ear infection is usually rapid.

Children

Signs and symptoms common in children include:

• Ear pain, especially when lying down
• Tugging or pulling at an ear
• Difficulty sleeping
• Crying more than usual
• Acting more irritable than usual
• Difficulty hearing or responding to sounds
• Loss of balance
• Fever of 100 F (38 C) or higher
• Drainage of fluid from the ear
• Headache
• Loss of appetite

Adults

Common signs and symptoms in adults include:

• Ear pain
• Drainage of fluid from the ear
• Diminished hearing

When to see a doctor

Signs and symptoms of an ear infection can indicate a number of conditions. It’s important to get an accurate diagnosis and prompt treatment. Call your child’s doctor if:

• Symptoms last for more than a day
• Symptoms are present in a child less than 6 months of age
• Ear pain is severe
• Your infant or toddler is sleepless or irritable after a cold or other upper respiratory infection
• You observe a discharge of fluid, pus or bloody discharge from the ear

An adult with ear pain or discharge should see a doctor as soon as possible.

Causes of middle ear infection

An ear infection is caused by a bacterium or virus in the middle ear. This infection often results from another illness — cold, flu or allergy — that causes congestion and swelling of the nasal passages, throat and eustachian tubes.

Role of eustachian tubes

The eustachian tubes are a pair of narrow tubes that run from each middle ear to high in the back of the throat, behind the nasal passages. The throat end of the tubes open and close to:

• Regulate air pressure in the middle ear
• Refresh air in the ear
• Drain normal secretions from the middle ear

Swelling, inflammation and mucus in the eustachian tubes from an upper respiratory infection or allergy can block them, causing the accumulation of fluids in the middle ear. A bacterial or viral infection of this fluid is usually what produces the symptoms of an ear infection.

Ear infections are more common in children, in part, because their eustachian tubes are narrower and more horizontal — factors that make them more difficult to drain and more likely to get clogged.

Role of adenoids

Adenoids are two small pads of tissues high in the back of the nose believed to play a role in immune system activity. This function may make them particularly vulnerable to infection, inflammation and swelling.

Because adenoids are near the opening of the eustachian tubes, inflammation or enlargement of the adenoids may block the tubes, thereby contributing to middle ear infection. Inflammation of adenoids is more likely to play a role in ear infections in children because children have relatively larger adenoids.

Related conditions

Conditions of the middle ear that may be related to an ear infection or result in similar middle ear problems include the following:

• Otitis media with effusion is inflammation and fluid buildup (effusion) in the middle ear without bacterial or viral infection. This may occur because the fluid buildup persists after an ear infection has resolved. It may also occur because of some dysfunction or noninfectious blockage of the eustachian tubes.
• Chronic otitis media with effusion occurs when fluid remains in the middle ear and continues to return without bacterial or viral infection. This makes children susceptible to new ear infections, and may affect hearing.
• Chronic suppurative otitis media is a persistent ear infection that often results in tearing or perforation of the eardrum.

Risk factors for middle ear infection

Risk factors for ear infections include:

• Age. Children between the ages of 6 months and 2 years are more susceptible to ear infections because of the size and shape of their eustachian tubes and because of their poorly developed immune systems.
• Group child care. Children cared for in group settings are more likely to get colds and ear infections than are children who stay home because they’re exposed to more infections, such as the common cold.
• Infant feeding. Babies who drink from a bottle, especially while lying down, tend to have more ear infections than do babies who are breast-fed.
• Seasonal factors. Ear infections are most common during the fall and winter when colds and flu are prevalent. People with seasonal allergies may have a greater risk of ear infections during seasonal high pollen counts.
• Poor air quality. Exposure to tobacco smoke or high levels of air pollution can increase the risk of ear infection.

Complications of middle ear infection

Most ear infections don’t cause long-term complications. Frequent or persistent infections and persistent fluid buildup can result in some serious complications:

• Impaired hearing. Mild hearing loss that comes and goes is fairly common with an ear infection, but it usually returns to what it was before the infection after the infection clears. Persistent infection or persistent fluids in the middle ear may result in more significant hearing loss. If there is some permanent damage to the eardrum or other middle ear structures, permanent hearing loss may occur.
• Speech or developmental delays. If hearing is temporarily or permanently impaired in infants and toddlers, they may experience delays in speech, social and developmental skills.
• Spread of infection. Untreated infections or infections that don’t respond well to treatment can spread to nearby tissues. Infection of the mastoid, the bony protrusion behind the ear, is called mastoiditis. This infection can result in damage to the bone and the formation of pus-filled cysts. Rarely, serious middle ear infections spread to other tissues in the skull, including the brain or the membranes surrounding the brain (meningitis).
• Tearing of the eardrum. Most eardrum tears heal within 72 hours. In some cases, surgical repair is needed.

Prevention of middle ear infection

The following tips may reduce the risk of developing ear infections:

• Prevent common colds and other illnesses. Teach your children to wash their hands frequently and thoroughly and to not share eating and drinking utensils. Teach your children to cough or sneeze into their arm crook. If possible, limit the time your child spends in group child care. A child care setting with fewer children may help. Try to keep your child home from child care or school when ill.
• Avoid secondhand smoke. Make sure that no one smokes in your home. Away from home, stay in smoke-free environments.
• Breast-feed your baby. If possible, breast-feed your baby for at least six months. Breast milk contains antibodies that may offer protection from ear infections.
• If you bottle-feed, hold your baby in an upright position. Avoid propping a bottle in your baby’s mouth while he or she is lying down. Don’t put bottles in the crib with your baby.
• Talk to your doctor about vaccinations. Ask your doctor about what vaccinations are appropriate for your child. Seasonal flu shots, pneumococcal and other bacterial vaccines may help prevent ear infections.

Diagnosis of middle ear infection

Your doctor can usually diagnose an ear infection or another condition based on the symptoms you describe and an exam. The doctor will likely use a lighted instrument (an otoscope) to look at the ears, throat and nasal passage. He or she will also likely listen to your child breathe with a stethoscope.

Pneumatic otoscope

An instrument called a pneumatic otoscope is often the only specialized tool a doctor needs to make a diagnosis of an ear infection. This instrument enables the doctor to look in the ear and judge whether there is fluid behind the eardrum. With the pneumatic otoscope, the doctor gently puffs air against the eardrum. Normally, this puff of air would cause the eardrum to move. If the middle ear is filled with fluid, your doctor will observe little to no movement of the eardrum.

Additional tests

Your doctor may perform other diagnostic tests if there is any doubt about a diagnosis, if the condition hasn’t responded to previous treatments, or if there are other persistent or serious problems.

• Tympanometry. This test measures the movement of the eardrum. The device, which seals off the ear canal, adjusts air pressure in the canal, thereby causing the eardrum to move. The device quantifies how well the eardrum moves and provides an indirect measure of pressure within the middle ear.
• Acoustic reflectometry. This test measures how much sound emitted from a device is reflected back from the eardrum — an indirect measure of fluids in the middle ear. Normally, the eardrum absorbs most of the sound. However, the more pressure there is from fluid in the middle ear, the more sound the eardrum will reflect.
• Tympanocentesis. Rarely, a doctor may use a tiny tube that pierces the eardrum to drain fluid from the middle ear — a procedure called tympanocentesis. Tests to determine the infectious agent in the fluid may be beneficial if an infection hasn’t responded well to previous treatments.
  Other tests. If your child has had persistent ear infections or persistent fluid buildup in the middle ear, your doctor may refer you to a hearing specialist (audiologist), speech therapist or developmental therapist for tests of hearing, speech skills, language comprehension or developmental abilities.

What a diagnosis means

• Acute otitis media. The diagnosis of “ear infection” is generally shorthand for acute otitis media. Your doctor likely makes this diagnosis if he or she observes signs of fluid in the middle ear, if there are signs or symptoms of an infection, and if the onset of symptoms was relatively sudden.
• Otitis media with effusion. If the diagnosis is otitis media with effusion, the doctor has found evidence of fluid in the middle ear, but there are presently no signs or symptoms of infection.
• Chronic suppurative otitis media. If the doctor makes a diagnosis of chronic suppurative otitis media, he or she has found that a persistent ear infection resulted in tearing or perforation of the eardrum.

Treatment for middle ear infection

Some ear infections resolve without treatment with antibiotics. What’s best for your child depends on many factors, including your child’s age and the severity of symptoms.

A wait-and-see approach

Symptoms of ear infections usually improve within the first couple of days, and most infections clear up on their own within one to two weeks without any treatment. The American Academy of Pediatrics and the American Academy of Family Physicians recommend a wait-and-see approach as one option for:

• Children 6 to 23 months with mild inner ear pain in one ear for less than 48 hours and a temperature less than 102.2 F (39 C)
• Children 24 months and older with mild inner ear pain in one or both ears for less than 48 hours and a temperature less than 102.2 F (39 C)

Some evidence suggests that treatment with antibiotics might be beneficial for certain children with ear infections. Talk to your doctor about the benefits of antibiotics weighed against the potential side effects and concern about overuse of antibiotics creating strains of resistant disease.

Managing pain

Your doctor will advise you on treatments to lessen pain from an ear infection. These may include the following:

• A warm compress. Placing a warm, moist washcloth over the affected ear may lessen pain.
• Pain medication. Your doctor may advise the use of over-the-counter acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin IB, others) to relieve pain. Use the drugs as directed on the label. Use caution when giving aspirin to children or teenagers. Children and teenagers recovering from chickenpox or flu-like symptoms should never take aspirin because aspirin has been linked with Reye’s syndrome. Talk to your doctor if you have concerns.

Antibiotic therapy

After an initial observation period, your doctor may recommend antibiotic treatment for an ear infection in the following situations:

• Children 6 months and older with moderate to severe ear pain in one or both ears for at least 48 hours or a temperature of 102.2 F (39 C) or higher
• Children 6 to 23 months with mild inner ear pain in one or both ears for less than 48 hours and a temperature less than 102.2 F (39 C)
• Children 24 months and older with mild inner ear pain in one or both ears for less than 48 hours and a temperature less than 102.2 F (39 C)

Children younger than 6 months of age with confirmed acute otitis media are more likely to be treated with antibiotics without the initial observational waiting time.

Even after symptoms have improved, be sure to use all of the antibiotic as directed. Failing to do so can result in recurring infection and resistance of bacteria to antibiotic medications. Talk to your doctor or pharmacist about what to do if you accidentally skip a dose.

Ear tubes

If your child has recurrent otitis media or otitis media with effusion, your doctor may recommend a procedure to drain fluid from the middle ear. Otitis media is defined as three episodes of infection in six months or four episodes of infection in a year with at least one occurring in the past six months. Otitis media with effusion is persistent fluid buildup in the ear after an infection has cleared up or in the absence of any infection.

During an outpatient surgical procedure called a myringotomy, a surgeon creates a tiny hole in the eardrum that enables him or her to suction fluids out of the middle ear. A tiny tube (tympanostomy tube) is placed in the opening to help ventilate the middle ear and prevent the accumulation of more fluids. Some tubes are intended to stay in place for six months to a year and then fall out on their own. Other tubes are designed to stay in longer and may need to be surgically removed.

The eardrum usually closes up again after the tube falls out or is removed.

Treatment for chronic suppurative otitis media

Chronic infection that results in perforation of the eardrum — chronic suppurative otitis media — is difficult to treat. It’s often treated with antibiotics administered as drops. You’ll receive instructions on how to suction fluids out through the ear canal before administering drops.

Monitoring

Children with frequent or persistent infections or with persistent fluid in the middle ear will need to be monitored closely. Talk to your doctor about how often you should schedule follow-up appointments. Your doctor may recommend regular hearing and language tests.

What is Tinnitus

Tinnitus is the perception of noise or ringing in the ears ⁴. A common problem, tinnitus affects about 1 in 5 people. Tinnitus isn’t a condition itself — it’s a symptom of an underlying condition, such as age-related hearing loss, ear injury or a circulatory system disorder.

Although bothersome, tinnitus usually isn’t a sign of something serious. Although it can worsen with age, for many people, tinnitus can improve with treatment. Treating an identified underlying cause sometimes helps. Other treatments reduce or mask the noise, making tinnitus less noticeable.

Symptoms of Tinnitus

Tinnitus involves the annoying sensation of hearing sound when no external sound is present. Tinnitus symptoms include these types of phantom noises in your ears:

• Ringing
• Buzzing
• Roaring
• Clicking
• Hissing

The phantom noise may vary in pitch from a low roar to a high squeal, and you may hear it in one or both ears. In some cases, the sound can be so loud it can interfere with your ability to concentrate or hear actual sound. Tinnitus may be present all the time, or it may come and go.

There are two kinds of tinnitus.

• Subjective tinnitus is tinnitus only you can hear. This is the most common type of tinnitus. It can be caused by ear problems in your outer, middle or inner ear. It also can be caused by problems with the hearing (auditory) nerves or the part of your brain that interprets nerve signals as sound (auditory pathways).
• Objective tinnitus is tinnitus your doctor can hear when he or she does an examination. This rare type of tinnitus may be caused by a blood vessel problem, a middle ear bone condition or muscle contractions.

When to see a doctor

If you have tinnitus that bothers you, see your doctor.

Make an appointment to see your doctor if:

• You develop tinnitus after an upper respiratory infection, such as a cold, and your tinnitus doesn’t improve within a week.

See your doctor as soon as possible if:

• You have tinnitus that occurs suddenly or without an apparent cause.
• You have hearing loss or dizziness with the tinnitus.

Causes of Tinnitus

A number of health conditions can cause or worsen tinnitus. In many cases, an exact cause is never found.

A common cause of tinnitus is inner ear cell damage. Tiny, delicate hairs in your inner ear move in relation to the pressure of sound waves. This triggers ear cells to release an electrical signal through a nerve from your ear (auditory nerve) to your brain. Your brain interprets these signals as sound. If the hairs inside your inner ear are bent or broken, they can “leak” random electrical impulses to your brain, causing tinnitus.

Other causes of tinnitus include other ear problems, chronic health conditions, and injuries or conditions that affect the nerves in your ear or the hearing center in your brain.

Common causes of tinnitus

In many people, tinnitus is caused by one of these conditions:

• Age-related hearing loss. For many people, hearing worsens with age, usually starting around age 60. Hearing loss can cause tinnitus. The medical term for this type of hearing loss is presbycusis.
• Exposure to loud noise. Loud noises, such as those from heavy equipment, chain saws and firearms, are common sources of noise-related hearing loss.
• Portable music devices, such as MP3 players or iPods, also can cause noise-related hearing loss if played loudly for long periods. Tinnitus caused by short-term exposure, such as attending a loud concert, usually goes away; long-term exposure to loud sound can cause permanent damage.
• Earwax blockage. Earwax protects your ear canal by trapping dirt and slowing the growth of bacteria. When too much earwax accumulates, it becomes too hard to wash away naturally, causing hearing loss or irritation of the eardrum, which can lead to tinnitus.
• Ear bone changes. Stiffening of the bones in your middle ear (otosclerosis) may affect your hearing and cause tinnitus. This condition, caused by abnormal bone growth, tends to run in families.

Other causes of tinnitus

Some causes of tinnitus are less common, including:

• Meniere’s disease. Tinnitus can be an early indicator of Meniere’s disease, an inner ear disorder that may be caused by abnormal inner ear fluid pressure.
• TMJ disorders. Problems with the temporomandibular joint, the joint on each side of your head in front of your ears, where your lower jawbone meets your skull, can cause tinnitus.
• Head injuries or neck injuries. Head or neck trauma can affect the inner ear, hearing nerves or brain function linked to hearing. Such injuries generally cause tinnitus in only one ear.
• Acoustic neuroma. This noncancerous (benign) tumor develops on the cranial nerve that runs from your brain to your inner ear and controls balance and hearing. Also called vestibular schwannoma, this condition generally causes tinnitus in only one ear.

Blood vessel disorders linked to tinnitus

In rare cases, tinnitus is caused by a blood vessel disorder. This type of tinnitus is called pulsatile tinnitus. Causes include:

• Atherosclerosis. With age and buildup of cholesterol and other deposits, major blood vessels close to your middle and inner ear lose some of their elasticity — the ability to flex or expand slightly with each heartbeat. That causes blood flow to become more forceful, making it easier for your ear to detect the beats. You can generally hear this type of tinnitus in both ears.
• Head and neck tumors. A tumor that presses on blood vessels in your head or neck (vascular neoplasm) can cause tinnitus and other symptoms.
• High blood pressure. Hypertension and factors that increase blood pressure, such as stress, alcohol and caffeine, can make tinnitus more noticeable.
• Turbulent blood flow. Narrowing or kinking in a neck artery (carotid artery) or vein in your neck (jugular vein) can cause turbulent, irregular blood flow, leading to tinnitus.
• Malformation of capillaries. A condition called arteriovenous malformation (AVM), abnormal connections between arteries and veins, can result in tinnitus. This type of tinnitus generally occurs in only one ear.

Medications that can cause tinnitus

A number of medications may cause or worsen tinnitus. Generally, the higher the dose of these medications, the worse tinnitus becomes. Often the unwanted noise disappears when you stop using these drugs. Medications known to cause or worsen tinnitus include:

• Antibiotics, including polymyxin B, erythromycin, vancomycin and neomycin
• Cancer medications, including mechlorethamine and vincristine
• Water pills (diuretics), such as bumetanide, ethacrynic acid or furosemide
• Quinine medications used for malaria or other health conditions
• Certain antidepressants may worsen tinnitus
• Aspirin taken in uncommonly high doses (usually 12 or more a day)

Risk factors for Tinnitus

Anyone can experience tinnitus, but these factors may increase your risk:

• Loud noise exposure. Prolonged exposure to loud noise can damage the tiny sensory hair cells in your ear that transmit sound to your brain. People who work in noisy environments — such as factory and construction workers, musicians, and soldiers — are particularly at risk.
• Age. As you age, the number of functioning nerve fibers in your ears declines, possibly causing hearing problems often associated with tinnitus.
• Gender. Men are more likely to experience tinnitus.
• Smoking. Smokers have a higher risk of developing tinnitus.
• Cardiovascular problems. Conditions that affect your blood flow, such as high blood pressure or narrowed arteries (atherosclerosis), can increase your risk of tinnitus.

Complications of Tinnitus

Tinnitus can significantly affect quality of life. Although it affects people differently, if you have tinnitus, you also may experience:

• Fatigue
• Stress
• Sleep problems
• Trouble concentrating
• Memory problems
• Depression
• Anxiety and irritability

Treating these linked conditions may not affect tinnitus directly, but it can help you feel better.

Prevention of Tinnitus

In many cases, tinnitus is the result of something that can’t be prevented. However, some precautions can help prevent certain kinds of tinnitus.

• Use hearing protection. Over time, exposure to loud noise can damage the nerves in the ears, causing hearing loss and tinnitus. If you use chain saws, are a musician, work in an industry that uses loud machinery or use firearms (especially pistols or shotguns), always wear over-the-ear hearing protection.
• Turn down the volume. Long-term exposure to amplified music with no ear protection or listening to music at very high volume through headphones can cause hearing loss and tinnitus.
• Take care of your cardiovascular health. Regular exercise, eating right and taking other steps to keep your blood vessels healthy can help prevent tinnitus linked to blood vessel disorders.

Diagnosis of Tinnitus

Your doctor will examine your ears, head and neck to look for possible causes of tinnitus. Tests include:

• Hearing (audiological) exam. As part of the test, you’ll sit in a soundproof room wearing earphones through which will be played specific sounds into one ear at a time. You’ll indicate when you can hear the sound, and your results are compared with results considered normal for your age. This can help rule out or identify possible causes of tinnitus.
• Movement. Your doctor may ask you to move your eyes, clench your jaw, or move your neck, arms and legs. If your tinnitus changes or worsens, it may help identify an underlying disorder that needs treatment.
• Imaging tests. Depending on the suspected cause of your tinnitus, you may need imaging tests such as CT or MRI scans.

The sounds you hear can help your doctor identify a possible underlying cause.

• Clicking. Muscle contractions in and around your ear can cause sharp clicking sounds that you hear in bursts. They may last from several seconds to a few minutes.
• Rushing or humming. Usually vascular in origin, you may notice sound fluctuations when you exercise or change positions, such as when you lie down or stand up.
• Heartbeat. Blood vessel problems, such as high blood pressure, an aneurysm or a tumor, and blockage of the ear canal or eustachian tube can amplify the sound of your heartbeat in your ears (pulsatile tinnitus).
• Low-pitched ringing. Conditions that can cause low-pitched ringing in one ear include Meniere’s disease. Tinnitus may become very loud before an attack of vertigo — a sense that you or your surroundings are spinning or moving.
• High-pitched ringing. Exposure to a very loud noise or a blow to the ear can cause a high-pitched ringing or buzzing that usually goes away after a few hours. However, if there’s hearing loss as well, tinnitus may be permanent. Long-term noise exposure, age-related hearing loss or medications can cause a continuous, high-pitched ringing in both ears. Acoustic neuroma can cause continuous, high-pitched ringing in one ear.
• Other sounds. Stiff inner ear bones (otosclerosis) can cause low-pitched tinnitus that may be continuous or may come and go. Earwax, foreign bodies or hairs in the ear canal can rub against the eardrum, causing a variety of sounds.

In many cases, the cause of tinnitus is never found. Your doctor can discuss with you steps you can take to reduce the severity of your tinnitus or to help you cope better with the noise.

Treatment of Tinnitus

Treating an underlying health condition

To treat your tinnitus, your doctor will first try to identify any underlying, treatable condition that may be associated with your symptoms. If tinnitus is due to a health condition, your doctor may be able to take steps that could reduce the noise. Examples include:

• Earwax removal. Removing impacted earwax can decrease tinnitus symptoms.
• Treating a blood vessel condition. Underlying vascular conditions may require medication, surgery or another treatment to address the problem.
• Changing your medication. If a medication you’re taking appears to be the cause of tinnitus, your doctor may recommend stopping or reducing the drug, or switching to a different medication.

Noise suppression

In some cases white noise may help suppress the sound so that it’s less bothersome. Your doctor may suggest using an electronic device to suppress the noise. Devices include:

• White noise machines. These devices, which produce simulated environmental sounds such as falling rain or ocean waves, are often an effective treatment for tinnitus. You may want to try a white noise machine with pillow speakers to help you sleep. Fans, humidifiers, dehumidifiers and air conditioners in the bedroom also may help cover the internal noise at night.
• Hearing aids. These can be especially helpful if you have hearing problems as well as tinnitus.
• Masking devices. Worn in the ear and similar to hearing aids, these devices produce a continuous, low-level white noise that suppresses tinnitus symptoms.
• Tinnitus retraining. A wearable device delivers individually programmed tonal music to mask the specific frequencies of the tinnitus you experience. Over time, this technique may accustom you to the tinnitus, thereby helping you not to focus on it. Counseling is often a component of tinnitus retraining.

Medications

Drugs can’t cure tinnitus, but in some cases they may help reduce the severity of symptoms or complications. Possible medications include:

• Tricyclic antidepressants, such as amitriptyline and nortriptyline, have been used with some success. However, these medications are generally used for only severe tinnitus, as they can cause troublesome side effects, including dry mouth, blurred vision, constipation and heart problems.
• Alprazolam (Niravam, Xanax) may help reduce tinnitus symptoms, but side effects can include drowsiness and nausea. It can also become habit-forming.

Home remedies for Tinnitus

Often, tinnitus can’t be treated. Some people, however, get used to it and notice it less than they did at first. For many people, certain adjustments make the symptoms less bothersome. These tips may help:

• Avoid possible irritants. Reduce your exposure to things that may make your tinnitus worse. Common examples include loud noises, caffeine and nicotine.
• Cover up the noise. In a quiet setting, a fan, soft music or low-volume radio static may help mask the noise from tinnitus.
• Manage stress. Stress can make tinnitus worse. Stress management, whether through relaxation therapy, biofeedback or exercise, may provide some relief.
• Reduce your alcohol consumption. Alcohol increases the force of your blood by dilating your blood vessels, causing greater blood flow, especially in the inner ear area.

Alternative medicine

There’s little evidence that alternative medicine treatments work for tinnitus. However, some alternative therapies that have been tried for tinnitus include:

• Acupuncture
• Hypnosis
• Ginkgo biloba
• Zinc supplements
• B vitamins

Neuromodulation using transcranial magnetic stimulation (TMS) is a painless, noninvasive therapy that has been successful in reducing tinnitus symptoms for some people. Currently, TMS is utilized more commonly in Europe and in some trials in the U.S. It is still to be determined which patients might benefit from such treatments.

Coping and support for Tinnitus

Tinnitus doesn’t always improve or completely go away with treatment. Here are some suggestions to help you cope:

• Counseling. A licensed therapist or psychologist can help you learn coping techniques to make tinnitus symptoms less bothersome. Counseling can also help with other problems often linked to tinnitus, including anxiety and depression.
• Support groups. Sharing your experience with others who have tinnitus may be helpful. There are tinnitus groups that meet in person, as well as Internet forums. To ensure the information you get in the group is accurate, it’s best to choose a group facilitated by a physician, audiologist or other qualified health professional.
• Education. Learning as much as you can about tinnitus and ways to alleviate symptoms can help. And just understanding tinnitus better makes it less bothersome for some people.

Balance problems

Balance problems are conditions that make you feel unsteady or dizzy. If you are standing, sitting or lying down, you might feel as if you are moving, spinning or floating. If you are walking, you might suddenly feel as if you are tipping over or generally unsteady.

Many body systems — including your muscles, bones, joints, vision, the balance organ in the inner ear, nerves, heart and blood vessels — must work normally for you to have normal balance. When these systems aren’t functioning well, you can experience balance problems.

Many medical conditions can cause balance problems. However, most balance problems result from issues in your balance end-organ in the inner ear (vestibular system).

Symptoms of balance problem

Signs and symptoms of balance problems include:

• Sense of motion or spinning (vertigo)
• Feeling of faintness (presyncope)
• Loss of balance (disequilibrium)
• Dizziness

Causes of balance problem

Balance problems can be caused by several different conditions. The cause of balance problems is usually related to the specific sign or symptom.
Sense of motion or spinning (vertigo)

Vertigo can be associated with many conditions, including:

• Benign paroxysmal positional vertigo (BPPV). BPPV occurs when calcium crystals in your inner ear — which help control your balance — are dislodged from their normal position and move elsewhere in the inner ear. BPPV is the most common cause of vertigo. You might experience a spinning sensation when turning in bed or tilting your head back to look up.
• Meniere’s disease. In addition to sudden and severe vertigo, Meniere’s disease can cause fluctuating hearing loss and buzzing, ringing or a feeling of fullness in your ear. The cause of Meniere’s disease isn’t fully known. Meniere’s disease is rare and typically develops in people who are between the ages of 20 and 60.
• Migraine. Dizziness and sensitivity to motion (vestibular migraine) can occur due to migraine headache. Migraine is a common cause of dizziness.
• Acoustic neuroma. This noncancerous (benign), slow-growing tumor develops on a nerve that affects your hearing and balance. You might experience dizziness or loss of balance, but the most common symptoms are hearing loss and ringing in your ear. Acoustic neuroma is a rare condition.
• Vestibular neuritis. This inflammatory disorder, probably caused by a virus, can affect the nerves in the balance portion of your inner ear. Symptoms are often severe and persistent, and include nausea and difficulty walking. Symptoms can last several days and gradually improve on their own.
• Ramsay Hunt syndrome. Also known as herpes zoster otitis, this condition occurs when a shingles infection affects the facial nerve near one of your ears. You might experience vertigo, ear pain and hearing loss.
• Head injury. You might experience vertigo due to a concussion or other head injury.
• Motion sickness. You might experience dizziness in boats, cars and airplanes, or on amusement park rides.
• Persistent postural-perceptual dizziness. This disorder occurs frequently with other types of vertigo. Symptoms include unsteadiness or a sensation of motion in your head. Symptoms often worsen when you watch objects move, when you read, or when you are in a visually complex environment such as a shopping mall.

Feeling of faintness (presyncope)

Presyncope can be associated with:

• Orthostatic hypotension (postural hypotension). Standing or sitting up too quickly can cause some people to experience a significant drop in their blood pressure, resulting in presyncope.
• Cardiovascular disease. Abnormal heart rhythms (heart arrhythmia), narrowed or blocked blood vessels, a thickened heart muscle (hypertrophic cardiomyopathy), or a decrease in blood volume can reduce blood flow and cause presyncope.

Loss of balance (disequilibrium)

Losing your balance while walking, or feeling imbalanced, can result from:

• Vestibular problems. Abnormalities in your inner ear can cause a sensation of a floating or heavy head, and unsteadiness in the dark.
• Nerve damage to your legs (peripheral neuropathy). The damage can lead to difficulties with walking.
• Joint, muscle or vision problems. Muscle weakness and unstable joints can contribute to your loss of balance. Difficulties with eyesight also can lead to disequilibrium.
• Medications. Disequilibrium can be a side effect of medications.
• Certain neurologic conditions. These include cervical spondylosis and Parkinson’s disease.

Dizziness

A sense of dizziness or lightheadedness can result from:

• Inner ear problems. Abnormalities of the vestibular system can lead to a sensation of floating or other false sensation of motion.
• Psychiatric disorders. Depression (major depressive disorder), anxiety and other psychiatric disorders can cause dizziness.
• Abnormally rapid breathing (hyperventilation). This condition often accompanies anxiety disorders and may cause lightheadedness.
• Medications. Lightheadedness can be a side effect of medications.

Diagnosis of balance problem

Your doctor will start by reviewing your medical history and conducting a physical and neurological examination.

To determine if your symptoms are caused by problems in the balance function in your inner ear, your doctor is likely to recommend tests. They might include:

• Hearing tests. Difficulties with hearing are frequently associated with balance problems.
• Posturography test. Wearing a safety harness, you try to remain standing on a moving platform. A posturography test indicates which parts of your balance system you rely on most.
• Electronystagmography and video nystagmography. Both tests record your eye movements, which play a role in vestibular function and balance. Electronystagmography uses electrodes and video nystagmography uses small cameras to record eye movements.
• Rotary chair test. Your eye movements are analyzed while you sit in a computer-controlled chair that moves slowly in one place in a circle.
• Dix-Hallpike maneuver. Your doctor carefully turns your head in different positions while watching your eye movements to determine if you have a false sense of motion or spinning.
• Vestibular evoked myogenic potentials test. Sensor pads attached to your neck and forehead and under your eyes measure tiny changes in muscle contractions in reaction to sounds.
• Imaging tests. MRI and CT scans can determine if underlying medical conditions might be causing your balance problem.
• Blood pressure and heart rate tests. Your blood pressure might be checked when sitting and then after standing for 2 to 3 minutes to determine if you have significant drops in blood pressure. Your heart rate might be checked when standing to help determine if a heart condition is causing your symptoms.

Treatment of balance problem

Treatment depends on the cause of your balance problems. Your treatment may include:

• Balance retraining exercises (vestibular rehabilitation). Therapists trained in balance problems design a customized program of balance retraining and exercises. Therapy can help you compensate for imbalance, adapt to less balance and maintain physical activity. To prevent falls, your therapist might recommend a balance aid, such as a cane, and ways to reduce your risk of falls in your home.
• Positioning procedures. If you have BPPV, a therapist might conduct a procedure (canalith repositioning) that clears particles out of your inner ear and deposits them into a different area of your ear. The procedure involves maneuvering the position of your head.
• Diet and lifestyle changes. If you have Meniere’s disease or migraine headaches, dietary changes are often suggested that can ease symptoms. If you experience orthostatic hypotension, you might need to drink more fluids or wear compressive stockings.
• Medications. If you have severe vertigo that lasts hours or days, you might be prescribed medications that can control dizziness and vomiting.
• Surgery. If you have Meniere’s disease or acoustic neuroma, your treatment team may recommend surgery. Stereotactic radiosurgery might be an option for some people with acoustic neuroma. This procedure delivers radiation precisely to your tumor and doesn’t require an incision.

What is hearing loss ?

The ear can be divided into three parts:

• The external ear includes the pinna (outer, visible ear) and the ear canal
• The middle ear includes the tympanic membrane (ear drum) and the ossicles (middle ear bones)
• The inner ear, which includes the cochlea (organ of hearing) and vestibule (organ of balance)

Sound waves enter the ear canal and cause a vibration of the tympanic membrane (ear drum) which is then passed through three tiny bones behind the ear drum in the middle ear space: the malleus (hammer), incus (anvil) and stapes (stirrup). The sound vibrations in the ossicles are then transmitted to the nerves and fluids in the cochlea (inner ear), which generates a nerve impulse that passes along the auditory nerve to the brain.

What are the types of hearing loss ?

Hearing loss can be divided into two types:

1. Conductive Hearing Loss, which is essentially a mechanical problem with the conduction of sound vibrations, and
2. Sensorineural Hearing Loss, a problem with the generation and/or transmission of nerve impulses from the inner ear to the brain.
3. Mixed hearing loss refers to a combination of these two types.

The preliminary classification of hearing loss as conductive or sensorineural can be determined by a physician using a tuning fork in the office. A formal audiogram, or hearing test, is the best way to determine the type and degree of hearing loss. The distinction between these two types of hearing loss is important because many cases of conductive hearing loss can be improved with medical or surgical intervention. An otolaryngologist, also called an Ear Nose and Throat or ENT doctor, can determine the specific diagnosis and treatments for either type of hearing loss and perform surgical treatments, if necessary.

What can cause Conductive Hearing Loss ?

Conductive hearing loss may result from diseases that affect the external ear or middle ear structures. Some of the causes of conductive hearing loss include:

Problems with the External Ear

• Cerumen (ear wax) obstruction: Ear wax can be identified by a medical examination and can usually be removed quickly. This condition may actually be aggravated by cotton tipped applicators (Q-tips) that many patients use in an attempt to clean their ears.
• Otitis Externa: Often referred to as “swimmer’s ear”, an infection of the ear canal may be related to water exposure. Although the most common symptoms of otitis externa are pain and tenderness of the ear, conductive hearing loss can also occur if there is severe swelling of the ear canal.
• Foreign body in Ear Canal: This is also readily identified on examination and can usually be cleared in the office. Occasionally, a brief anesthesia is required for this procedure in children. Common foreign bodies include beads and beans in children and cotton or the tips of cotton-tipped applicators in adults. Uncommonly, the foreign object is a live bug such as a cockroach which can cause itching, pain and noise.
• Bony lesions of Ear Canal: These are benign growths of bone along the walls of the ear canal resulting in a narrowing of the ear canal which may then lead to frequent obstruction from a small amount of wax or water. These bony lesions can generally be managed with vigilant cleaning of ear wax to prevent obstruction. In rare cases these lesions require surgical removal.
• Atresia of the Ear Canal: Complete malformation of the external ear canal is called atresia. It may be seen along with complete or partial malformation of the pinna (outer ear) and is noted at birth. It is rarely associated with other congenital abnormalities and is most often only on one side (unilateral). Management of congenital aural atresia is complex. Surgical treatment may be beneficial to either reconstruct the ear canal in select cases or to implant a device that vibrates the bone of the ear directly.

Problems with the Middle Ear structures

• Middle Ear Fluid or Infection (otitis media): The middle ear space may be filled with fluid instead of air. Otitis media is divided into three types: acute otitis media, serous otitis media (middle ear fluid) or chronic otitis media. Acute otitis media occurs rapidly, is painful, and may cause fever. Serous otitis media often follows an acute otitis media infection or may occur on its own. Both conditions are common in children and are related to an inability to ventilate the middle ear space due to poor Eustachian tube function (the channel which connects the middle ear space with the nasal passage). Otitis media may be treated medically or with a myringotomy with tube insertion (also known as an M&T or ear tube surgery). In most adults, an M&T surgery may be performed in the office. In children, a brief general anesthesia is usually required. Chronic otitis media is associated with damage to the ear drum or ossicles (middle ear bones), and frequently requires surgery.
• Tympanic Membrane Atelectasis or Retraction (collapse of the ear drum): Poor Eustachian tube function may also result in excessive negative pressure behind the ear drum causing the ear drum to collapse onto the middle ear bones. Severe retraction of the ear drum may necessitate ear tube surgery or a surgery to rebuild the ear drum (tympanoplasty).
• Tympanic Membrane Perforation: A hole in the ear drum due to infections or trauma may result in hearing loss as the sound vibrations are not effectively captured by the damaged ear drum. A tympanoplasty is the surgical repair of the ear drum. Generally, this is an outpatient surgery performed by an otolaryngologist with a very high success rate (over 90%).
• Cholesteatoma: This may develop when the ear drum collapses to the point that the outer skin of the ear drum grows into the middle ear and becomes trapped. In spite of the ending of the word cholesteatoma, this is not a tumor but a benign collection of skin that can cause destruction of the middle ear structures and, if left untreated, more serious problems. This is almost always a surgical disease and may require a staged surgical approach (more than one surgery) in order to safely remove the cholesteatoma and restore hearing by repairing the damaged middle ear bones.
• Damage to the Middle Ear Ossicles: This may result from trauma, infection, cholesteatoma or a retracted ear drum leading to conductive hearing loss. Surgical reconstruction of the ossicular chain is often successful in restoring hearing in these cases.
• Otosclerosis: This is an inherited disease in which the bone around the stapes bone hardens and the stapes fails to vibrate effectively. The conductive hearing loss slowly progresses in early adulthood. It affects women more often than men and affects slightly less than 1% of the population overall. This condition may be treated with a hearing aid or with a stapedectomy surgery which is highly effective in restoring hearing in most cases.

Many types of hearing loss can also be ameliorated with the use of conventional hearing aids. In addition, many implantable hearing devices are available for various types of hearing loss. An otolaryngologist can determine the specific cause of the hearing loss, advise patients of their treatment and rehabilitative options, and help patients achieve the best possible hearing outcome and hearing related quality of life.

When should a hearing test be performed related to frequent infections or fluid ?

A hearing test should be performed for children who have frequent ear infections, hearing loss that lasts more than six weeks, or fluid in the middle ear for more than three months. There are a wide range of medical devices now available to test a child’s hearing, Eustachian tube function, and flexibility of the ear drum. They include the otoscopy, tympanometer, and audiometer.

1. Swimmer’s ear. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/swimmers-ear/symptoms-causes/syc-20351682[↩][↩]
2. Ruptured eardrum (perforated eardrum). Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/ruptured-eardrum/symptoms-causes/syc-20351879[↩]
3. Ear infection (middle ear). Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/ear-infections/symptoms-causes/syc-20351616[↩]
4. Tinnitus. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/tinnitus/symptoms-causes/syc-20350156[↩]

What is ear canal

The external ear consists of the auricle and the external ear canal or external acoustic meatus. The auricle or pinna, is what most people call the ear—the shell-shaped projection that surrounds the opening of the external acoustic meatus. Most of the auricle, including the helix (rim), consists of elastic cartilage covered with skin. Its fleshy, dangling lobule (“earlobe”), however, lacks supporting cartilage. The function of the auricle is to gather and funnel (and thereby amplify) sound waves coming into the external acoustic meatus. Moreover, the way that sound bounces off the ridges and cavities of the auricle provides the brain with clues about whether sounds come from above or below.

The external ear canal (external acoustic meatus) is a short tube (about 2.5 cm long) running medially, from the auricle to the eardrum. Near the auricle, its wall consists of elastic cartilage, but its medial two-thirds tunnels through the temporal bone. The entire canal is lined with skin that contains hairs, as well as sebaceous glands and modified apocrine sweat glands called ceruminous glands. The ceruminous and sebaceous glands secrete yellow-brown cerumen, or earwax. Earwax traps dust and repels insects, keeping them out of the auditory canal.

Sound waves entering the external acoustic meatus hit the thin, translucent tympanic membrane, or eardrum (tympanum = drum), which forms the boundary between the external and middle ears. The tympanic membrane is shaped like a flattened cone, the apex of which points medially into the middle ear cavity. Sound waves that travel through the air set the eardrum vibrating, and the eardrum in turn transfers the vibrations to tiny bones in the middle ear.

Figure 1. Outer ear

Figure 2. Ear anatomy

Swimmer’s ear

Swimmer’s ear is an infection in the outer ear canal, which runs from your eardrum to the outside of your head ¹. It’s often brought on by water that remains in your ear after swimming, creating a moist environment that aids bacterial growth.

Putting fingers, cotton swabs or other objects in your ears also can lead to swimmer’s ear by damaging the thin layer of skin lining your ear canal ¹.

Swimmer’s ear is also known as otitis externa. The most common cause of this infection is bacteria invading the skin inside your ear canal. Usually you can treat swimmer’s ear with eardrops. Prompt treatment can help prevent complications and more-serious infections.

Causes of Swimmer’s ear

Swimmer’s ear is an infection that’s usually caused by bacteria commonly found in water and soil. Infections caused by a fungus or a virus are less common. Swimmer’s ear is more common among children in their teens and young adults. It may occur with a middle ear infection or a respiratory infection such as a cold.

Swimming in unclean water can lead to swimmer’s ear. Bacteria commonly often found in water can cause ear infections. Rarely, the infection may be caused by a fungus.

Other causes of swimmer’s ear include:

• Scratching the ear or inside the ear
• Getting something stuck in the ear

Trying to clean (wax from the ear canal) with cotton swabs or small objects can damage the skin.

Long-term (chronic) swimmer’s ear may be due to:

• Allergic reaction to something placed in the ear
• Chronic skin conditions, such as eczema or psoriasis

Your ear’s natural defenses

Your outer ear canals have natural defenses that help keep them clean and prevent infection. Protective features include:

• Glands that secrete a waxy substance (cerumen). These secretions form a thin, water-repellent film on the skin inside your ear. Cerumen is also slightly acidic, which helps further discourage bacterial growth. In addition, cerumen collects dirt, dead skin cells and other debris and helps move these particles out of your ear. The waxy clump that results is the familiar earwax you find at the opening of your ear canal.

• Downward slope of your ear canal. Your ear canal slopes down slightly from your middle ear to your outer ear, helping water drain out.

How the swimmer’s ear occurs

If you have swimmer’s ear, your natural defenses have been overwhelmed. Conditions that can weaken your ear’s defenses and promote bacterial growth include:

• Excess moisture in your ear. Heavy perspiration, prolonged humid weather or water that remains in your ear after swimming can create a favorable environment for bacteria.
• Scratches or abrasions in your ear canal. Cleaning your ear with a cotton swab or hairpin, scratching inside your ear with a finger, or wearing headphones or hearing aids can cause small breaks in the skin that allow bacteria to grow.
• Sensitivity reactions. Hair products or jewelry can cause allergies and skin conditions that promote infection.

Risk factors for swimmer’s ear

Factors that may increase your risk of swimmer’s ear include:

• Swimming
• Swimming in water with elevated bacteria levels, such as a lake rather than a well-maintained pool
• A narrow ear canal — for example, in a child — that can more easily trap water
• Aggressive cleaning of the ear canal with cotton swabs or other objects
• Use of certain devices, such as headphones or a hearing aid
• Skin allergies or irritation from jewelry, hair spray or hair dyes.

Table 1. Predisposing factors for outer ear infection (swimmer’s ear)

Symptoms of Swimmer’s ear

Swimmer’s ear symptoms are usually mild at first, but they may get worse if your infection isn’t treated or spreads. Doctors often classify swimmer’s ear according to mild, moderate and advanced stages of progression.

Mild signs and symptoms

• Itching in your ear canal
• Slight redness inside your ear
• Mild discomfort that’s made worse by pulling on your outer ear (pinna, or auricle) or pushing on the little “bump” (tragus) in front of your ear
• Some drainage of clear, odorless fluid

Moderate progression

• More intense itching
• Increasing pain
• More extensive redness in your ear
• Excessive fluid drainage
• Discharge of pus
• Feeling of fullness inside your ear and partial blockage of your ear canal by swelling, fluid and debris
• Decreased or muffled hearing

Advanced progression

• Severe pain that may radiate to your face, neck or side of your head
• Complete blockage of your ear canal
• Redness or swelling of your outer ear
• Swelling in the lymph nodes in your neck
• Fever

When to see a doctor

See your doctor if you’re experiencing any signs or symptoms of swimmer’s ear, even if they’re mild.

Call your doctor immediately or visit the emergency room if you have:

• Severe pain
• Fever

Complications of Swimmer’s ear

Swimmer’s ear usually isn’t serious if treated promptly, but complications can occur.

• Temporary hearing loss. You may experience muffled hearing that usually gets better after the infection clears up.
• Long-term infection (chronic otitis externa). An outer ear infection is usually considered chronic if signs and symptoms persist for more than three months.
• Chronic infections are more common if there are conditions that make treatment difficult, such as a rare strain of bacteria, an allergic skin reaction, an allergic reaction to antibiotic eardrops, or a combination of a bacterial and fungal infection.
• Deep tissue infection (cellulitis). Rarely, swimmer’s ear may result in the spread of infection into deep layers and connective tissues of the skin.
• Bone and cartilage damage (necrotizing otitis externa). An outer ear infection that spreads can cause inflammation and damage to the skin and cartilage of the outer ear and bones of the lower part of the skull, causing increasingly severe pain. Older adults, people with diabetes or people with weakened immune systems are at increased risk of this complication. Necrotizing otitis externa is also known as malignant otitis externa, but it’s not a cancer.
• More widespread infection. If swimmer’s ear develops into necrotizing otitis externa, the infection may spread and affect other parts of your body, such as the brain or nearby nerves. This rare complication can be life-threatening.

Prevention of Swimmer’s ear

Follow these tips to avoid swimmer’s ear:

• Keep your ears dry. Dry your ears thoroughly after exposure to moisture from swimming or bathing. Dry only your outer ear, wiping it slowly and gently with a soft towel or cloth. Tip your head to the side to help water drain from your ear canal. You can dry your ears with a blow dryer if you put it on the lowest setting and hold it at least a foot (about 0.3 meters) away from the ear.
• At-home preventive treatment. If you know you don’t have a punctured eardrum, you can use homemade preventive eardrops before and after swimming. A mixture of 1 part white vinegar to 1 part rubbing alcohol may help promote drying and prevent the growth of bacteria and fungi that can cause swimmer’s ear. Pour 1 teaspoon (about 5 milliliters) of the solution into each ear and let it drain back out. Similar over-the-counter solutions may be available at your drugstore.
• Swim wisely. Watch for signs alerting swimmers to high bacterial counts and don’t swim on those days.
• DO NOT scratch the ears or insert cotton swabs or other objects in the ears.
• Avoid putting foreign objects in your ear. Never attempt to scratch an itch or dig out earwax with items such as a cotton swab, paper clip or hairpin. Using these items can pack material deeper into your ear canal, irritate the thin skin inside your ear or break the skin.
• Protect your ears from irritants. Put cotton balls in your ears while applying products such as hair sprays and hair dyes.
• Use caution after an ear infection or surgery. If you’ve recently had an ear infection or ear surgery, talk to your doctor before you go swimming.

Diagnosis of swimmer’s ear

Doctors can usually diagnose swimmer’s ear during an office visit. If your infection is at an advanced stage or persists, you may need further evaluation.
Initial testing

Your doctor will likely diagnose swimmer’s ear based on symptoms you report, questions he or she asks, and an office examination. You probably won’t need a lab test at your first visit. Your doctor’s initial evaluation will usually include:

• Examination of your ear canal with a lighted instrument (otoscope). Your ear canal may appear red, swollen and scaly. Flakes of skin and other debris may be present in the ear canal.
• Visualization of your eardrum (tympanic membrane) to be sure it isn’t torn or damaged. If the view of your eardrum is blocked, your doctor will clear your ear canal with a small suction device or an instrument with a tiny loop or scoop on the end (ear curette).

Further testing

Depending on the initial assessment, symptom severity or the stage of your swimmer’s ear, your doctor may recommend additional evaluation.

• If your eardrum is damaged or torn, your doctor will likely refer you to an ear, nose and throat specialist (ENT). The specialist will examine the condition of your middle ear to determine if that’s the primary site of infection. This examination is important because some treatments intended for an infection in the outer ear canal aren’t appropriate for treating the middle ear.

• If your infection doesn’t respond to treatment, your doctor may take a sample of discharge or debris from your ear at a later appointment and send it to a lab to identify the exact microorganism causing your infection.

Table 2. Conditions That May Be Confused with Swimmer’s Ear (Acute Outer Ear Infection)

Treatment for swimmer’s ear

The goal of treatment is to stop the infection and allow your ear canal to heal.

Cleaning

Cleaning your outer ear canal is necessary to help eardrops flow to all infected areas. Your doctor will use a suction device or ear curette to clean away any discharge, clumps of earwax, flaky skin and other debris.

Medications for infection

For most cases of swimmer’s ear, your doctor will prescribe eardrops that have some combination of the following ingredients, depending on the type and seriousness of your infection:

• Acidic solution to help restore your ear’s normal antibacterial environment
• Steroid to reduce inflammation
• Antibiotic to fight bacteria
• Antifungal medication to fight an infection caused by a fungus

Ask your doctor about the best method for taking your eardrops. Some ideas that may help you use eardrops include the following:

• Reduce the discomfort of cool drops by holding the bottle in your hand for a few minutes to bring the temperature of the drops closer to body temperature.
• Lie on your side with your infected ear up for a few minutes to help medication travel through the full length of your ear canal.
• If possible, have someone help you put the drops in your ear.

If your ear canal is completely blocked by swelling, inflammation or excess discharge, your doctor may insert a wick made of cotton or gauze to promote drainage and help draw medication into your ear canal.

If your infection is more advanced or doesn’t respond to treatment with eardrops, your doctor may prescribe oral antibiotics.

Medications for pain

Your doctor may recommend easing the discomfort of swimmer’s ear with over-the-counter pain relievers, such as ibuprofen (Advil, Motrin IB, others), naproxen sodium (Aleve, others) or acetaminophen (Tylenol, others).

If your pain is severe or your swimmer’s ear is at a more advanced stage, your doctor may prescribe a stronger medication for pain relief.

Helping your treatment work

During treatment, the following steps will help keep your ears dry and avoid further irritation:

• Don’t swim or scuba dive.
• Avoid flying.
• Don’t wear an earplug, hearing aid or headphones before pain or discharge has stopped.
• Avoid getting water in your ear canal when bathing. Use a cotton ball coated with petroleum jelly to protect your ear during a bath.

Prevention of Outer Ear Infection

A number of preventive measures have been recommended, including use of earplugs while swimming, use of hair dryers on the lowest settings and head tilting to remove water from the ear canal, and avoidance of self-cleaning or scratching the ear canal. Acetic acid 2% (Vosol) otic solutions are also used, either two drops twice daily or two to five drops after water exposure. However, no randomized trials have examined the effectiveness of any of these measures.

Chronic Outer Ear Infection

In chronic outer ear infection (chronic otitis externa), the symptoms and signs occur for more than three months. Classic symptoms include itching and mild discomfort; there may also be lichenification on otoscopy.

Treatment of outer ear infection

TOPICAL MEDICATIONS

Topical antimicrobials, with or without topical corticosteroids, are the mainstay of treatment for uncomplicated acute outer ear infection. Topical antimicrobials are highly effective compared with placebo, demonstrating an absolute increase in clinical cure rate of 46 percent or a number needed to treat of slightly more than two ³. Topical agents come in a variety of preparations and combinations; a recent systematic review included 26 different topical interventions ⁴. In some studies, ophthalmic preparations have been used off-label to treat outer ear infection ⁵, ⁴. Ophthalmic preparations may be better tolerated than otic preparations, possibly due to differences in pH between the preparations, and may help facilitate compliance with treatment recommendations. Commonly studied antimicrobial agents include aminoglycosides, polymyxin B, quinolones, and acetic acid. No consistent evidence has shown that any one agent or preparation is more effective than another ³, ⁶, ⁵, ⁴. There is limited evidence that use of acetic acid alone may require two additional days for resolution of symptoms compared with other agents, and that it is less effective if treatment is required for more than seven days ⁴.

Current guidelines recommend factoring in the risk of adverse effects, adherence issues, cost, patient preference, and physician experience. Some components found in otic preparations may cause contact dermatitis ⁷. Hypersensitivity to aminoglycosides, particularly neomycin, may develop in up to 15 percent of the population, and has been identified in approximately 30 percent of patients who also have chronic or eczematous outer ear infection ⁷, ⁸. Adherence to topical therapy increases with ease of administration, such as less frequent dosing ⁹. The addition of a topical corticosteroid yields more rapid improvement in symptoms such as pain, canal edema, and erythema. Cost varies considerably for the different preparations.

Outer Ear Infection Pain Relief

Pain is a common symptom of acute outer ear infection and can be debilitating ¹⁰. Oral analgesics are the preferred treatment. First-line analgesics include nonsteroidal anti-inflammatory drugs and acetaminophen. When ongoing frequent dosing is required to control pain, medications should be administered on a scheduled rather than as-needed basis. Opioid combination pills may be used when symptom severity warrants. Benzocaine otic preparations may compromise the effectiveness of otic antibiotic drops by limiting contact between the drop and the ear canal. The lack of published data supporting the effectiveness of topical benzocaine preparations in outer ear infection limits the role of such treatments ².

CLEANING THE EAR CANAL

Acute outer ear infection can be associated with copious material in the ear canal. Consensus guidelines published by the American Academy of Otolaryngology recommend that such material be removed to achieve optimal effectiveness of the topical antibiotics ³, ⁶. However, no randomized controlled trials have examined the effectiveness of aural toilet, and this is not typically done in most primary care settings ⁴. Topical medications rely on direct contact with the infected skin of the ear canal; hence, aural toilet takes on greater importance when the volume or thickness of the debris in the ear canal is great. Guidelines recommend aural toilet by gentle lavage suctioning or dry mopping under otoscopic or microscopic visualization to remove obstructing material and to verify tympanic membrane integrity ³. Lavage should be used only if the tympanic membrane is known to be intact, and should not be performed on patients with diabetes because of the potential risk of causing malignant outer ear infection ³. Pain medications may be required during the procedure.

Treatment of chronic outer ear infection

The treatment of chronic outer ear infection depends on the underlying causes. Because most cases are caused by allergies or inflammatory dermatologic conditions, treatment includes the removal of offending agents and the use of topical or systemic corticosteroids. Chronic or intermittent otorrhea over weeks to months, particularly with an open tympanic membrane, suggests the presence of chronic suppurative otitis media (suppurative middle ear infection). Initial treatment efforts are similar to those for acute otitis media. With control of the symptoms of outer ear infection, attention can shift to the management of chronic suppurative otitis media.

Follow-up and Referral

Most patients will experience considerable improvement in symptoms after one day of treatment. If there is no improvement within 48 to 72 hours, physicians should reevaluate for treatment adherence, misdiagnosis, sensitivity to ear drops, or continued canal patency. The physician should consider culturing material from the canal to identify fungal and antibiotic-resistant pathogens if the patient does not improve after initial treatment efforts or has one or more predisposing risk factors, or if there is suspicion that the infection has extended beyond the external auditory canal. There is a lack of data regarding optimal length of treatment; as a general rule, antimicrobial otics should be administered for seven to 10 days, although in some cases complete resolution of symptoms may take up to four weeks ³, ⁴.

Consultation with an otolaryngologist or infectious disease subspecialist may be warranted if malignant outer ear infection is suspected; in cases of severe disease, lack of improvement or worsening of symptoms despite treatment, and unsuccessful lavage; or if the primary care physician determines that aural toilet or ear wick insertion is warranted, but is unfamiliar with or concerned about performing the procedure.

1. Swimmer’s ear. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/swimmers-ear/symptoms-causes/syc-20351682[↩][↩]
2. Acute Otitis Externa: An Update. Am Fam Physician. 2012 Dec 1;86(11):1055-1061. http://www.aafp.org/afp/2012/1201/p1055.html[↩][↩][↩]
3. Rosenfeld RM, Brown L, Cannon CR, et al.; American Academy of Otolaryngology–Head and Neck Surgery Foundation. Clinical practice guideline: acute otitis externa. Otolaryngol Head Neck Surg. 2006;134(4 suppl):S4–S23.[↩][↩][↩][↩][↩][↩]
4. Kaushik V, Malik T, Saeed SR. Interventions for acute otitis externa. Cochrane Database Syst Rev. 2010(1):CD004740.[↩][↩][↩][↩][↩][↩]
5. Rosenfeld RM, Singer M, Wasserman JM, Stinnett SS. Systematic review of topical antimicrobial therapy for acute otitis externa. Otolaryngol Head Neck Surg. 2006;134(4 suppl):S24–S48.[↩][↩]
6. Hajioff D, Mackeith S. Otitis externa. Clin Evid (Online). 2010.[↩][↩]
7. Smith IM, Keay DG, Buxton PK. Contact hypersensitivity in patients with chronic otitis externa. Clin Otolaryngol Allied Sci. 1990;15(2):155–158.[↩][↩]
8. Yariktas M, Yildirim M, Doner F, Baysal V, Dogru H. Allergic contact dermatitis prevalence in patients with eczematous external otitis. Asian Pac J Allergy Immunol. 2004;22(1):7–10.[↩]
9. Shikiar R, Halpern MT, McGann M, Palmer CS, Seidlin M. The relation of patient satisfaction with treatment of otitis externa to clinical outcomes: development of an instrument. Clin Ther. 1999;21(6):1091–1104.[↩]
10. van Asperen IA, de Rover CM, Schijven JF, et al. Risk of otitis externa after swimming in recreational fresh water lakes containing Pseudomonas aeruginosa. BMJ. 1995;311(7017):1407–1410.[↩]

What is ear drum

The external (outer) ear consists of the auricle, external auditory canal, and eardrum (Figure 1 and 2). The auricle or pinna is a flap of elastic cartilage shaped like the flared end of a trumpet and covered by skin. The rim of the auricle is the helix; the inferior portion is the lobule. Ligaments and muscles attach the auricle to the head. The external auditory canal is a curved tube about 2.5 cm (1 in.) long that lies in the temporal bone and leads to the eardrum.

The tympanic membrane or ear drum is a thin, semitransparent partition between the external auditory canal and middle ear. The tympanic membrane is covered by epidermis and lined by simple cuboidal epithelium. Between the epithelial layers is connective tissue composed of collagen, elastic fibers, and fibroblasts. Tearing of the tympanic membrane is called a perforated eardrum. It may be due to pressure from a cotton swab, trauma, or a middle ear infection, and usually heals within a month. The tympanic membrane may be examined directly by an otoscope, a viewing instrument that illuminates and magnifies the external auditory canal and tympanic membrane.

The tympanic membrane is shaped like a flattened cone, the apex of which points medially into the middle ear cavity. Sound waves that travel through the air set  the eardrum vibrating, and the eardrum in turn transfers the vibrations to tiny bones in the middle ear.

Figure 1. Ear

Figure 2. Normal ear drum (tympanic membrane) (otoscopic view)

The middle ear is a small, air-filled cavity in the petrous portion of the temporal bone that is lined by epithelium. It is separated from the external ear by the tympanic membrane and from the internal ear by a thin bony partition that contains two small openings: the oval window and the round window.

Extending across the middle ear and attached to it by ligaments are the three smallest bones in the body, the auditory ossicles, which are connected by synovial joints. The bones, named for their shapes, are the malleus, incus, and stapes—commonly called the hammer, anvil, and stirrup, respectively. The “handle” of the malleus attaches to the internal surface of the tympanic membrane. The head of the malleus articulates with the body of the incus. The incus, the middle bone in the series, articulates with the head of the stapes. The base or footplate of the stapes fits into the oval window. Directly below the oval window is another opening, the round window, which is enclosed by a membrane called the secondary tympanic membrane. Besides the ligaments, two tiny skeletal muscles also attach to the ossicles (Figure 3 and 4).

The anterior wall of the middle ear contains an opening that leads directly into the auditory tube or pharyngotympanic tube, commonly known as the eustachian tube. The auditory tube, which consists of both bone and elastic cartilage, connects the middle ear with the nasopharynx (superior portion of the throat). It is normally closed at its medial (pharyngeal) end. During swallowing and yawning, it opens, allowing air to enter or leave the middle ear until the pressure in the middle ear equals the atmospheric pressure. Most of us have experienced our ears popping as the pressures equalize. When the pressures are balanced, the tympanic membrane vibrates freely as sound waves strike it. If the pressure is not equalized, intense pain, hearing impairment, ringing in the ears, and vertigo could develop. The auditory tube also is a route for pathogens to travel from the nose and throat to the middle ear, causing the most common type of ear infection.

Figure 3. Ear drum anatomy (tympanic membrane removed to reveal the middle ear bones or auditory ossicles)

Figure 4. Middle ear and auditory ossicles

Ruptured eardrum (perforated eardrum)

A ruptured eardrum — or tympanic membrane perforation as it’s medically known — is a hole or tear in the thin tissue that separates your ear canal from your middle ear (eardrum) ¹.

A ruptured eardrum can result in hearing loss. A ruptured eardrum can also make your middle ear vulnerable to infections or injury.

A ruptured eardrum usually heals within a few weeks without treatment. Sometimes, however, a ruptured eardrum requires a procedure or surgical repair to heal.

If you think that you have a ruptured eardrum, be careful to keep your ears dry to prevent infection. Don’t go swimming. To keep water out of your ear when showering or bathing, use a moldable, waterproof silicone earplug or put a cotton ball coated with petroleum jelly in your outer ear.

Don’t put medication drops in your ear unless your doctor prescribes them specifically for infection related to your perforated eardrum.

Causes of a ruptured or perforated eardrum

Causes of a ruptured, or perforated, eardrum may include:

• Middle ear infection (otitis media). A middle ear infection often results in the accumulation of fluids in your middle ear. Pressure from these fluids can cause the eardrum to rupture.
• Barotrauma. Barotrauma is stress exerted on your eardrum when the air pressure in your middle ear and the air pressure in the environment are out of balance. If the pressure is severe, your eardrum can rupture. Barotrauma is most often caused by air pressure changes associated with air travel.
• Other events that can cause sudden changes in pressure — and possibly a ruptured eardrum — include scuba diving and a direct blow to the ear, such as the impact of an automobile air bag.
• Loud sounds or blasts (acoustic trauma). A loud sound or blast, as from an explosion or gunshot — essentially an overpowering sound wave — can cause a tear in your eardrum.
• Foreign objects in your ear. Small objects, such as a cotton swab or hairpin, can puncture or tear the eardrum.
• Severe head trauma. Severe injury, such as skull fracture, may cause the dislocation or damage to middle and inner ear structures, including your eardrum.

Complications of of a ruptured or perforated eardrum

Your eardrum (tympanic membrane) has two primary roles:

• Hearing. When sound waves strike it, your eardrum vibrates — the first step by which structures of your middle and inner ears translate sound waves into nerve impulses.
• Protection. Your eardrum also acts as a barrier, protecting your middle ear from water, bacteria and other foreign substances.

If your eardrum ruptures, complications can occur while your eardrum is healing or if it fails to heal. Possible complications include:

• Hearing loss. Usually, hearing loss is temporary, lasting only until the tear or hole in your eardrum has healed. The size and location of the tear can affect the degree of hearing loss.
• Middle ear infection (otitis media). A perforated eardrum can allow bacteria to enter your ear. If a perforated eardrum doesn’t heal or isn’t repaired, you may be vulnerable to ongoing (chronic) infections that can cause permanent hearing loss.
• Middle ear cyst (cholesteatoma). A cholesteatoma is a cyst in your middle ear composed of skin cells and other debris. Ear canal debris normally travels to your outer ear with the help of ear-protecting earwax. If your eardrum is ruptured, the skin debris can pass into your middle ear and form a cyst. A cholesteatoma provides a friendly environment for bacteria and contains proteins that can damage bones of your middle ear.

Prevention of a ruptured or perforated eardrum

Follow these tips to avoid a ruptured or perforated eardrum:

• Get treatment for middle ear infections. Be aware of the signs and symptoms of middle ear infection, including earache, fever, nasal congestion and reduced hearing. Children with a middle ear infection often rub or pull on their ears. Seek prompt evaluation from your primary care doctor to prevent potential damage to the eardrum.
• Protect your ears during flight. If possible, don’t fly if you have a cold or an active allergy that causes nasal or ear congestion. During takeoffs and landings, keep your ears clear with pressure-equalizing earplugs, yawning or chewing gum. Or use the Valsalva maneuver — gently blowing, as if blowing your nose, while pinching your nostrils and keeping your mouth closed. Don’t sleep during ascents and descents.
• Keep your ears free of foreign objects. Never attempt to dig out excess or hardened earwax with items such as a cotton swab, paper clip or hairpin. These items can easily tear or puncture your eardrum. Teach your children about the damage that can be done by putting foreign objects in their ears.
• Guard against excessive noise. Protect your ears from unnecessary damage by wearing protective earplugs or earmuffs in your workplace or during recreational activities if loud noise is present.

Symptoms of a ruptured or perforated eardrum

Signs and symptoms of a ruptured eardrum may include:

• Ear pain that may subside quickly
• Clear, pus-filled or bloody drainage from your ear
• Hearing loss
• Ringing in your ear (tinnitus)
• Spinning sensation (vertigo)
• Nausea or vomiting that can result from vertigo

When to see a doctor

Call your doctor if you experience any of the signs or symptoms of a ruptured eardrum or pain or discomfort in your ears. Your middle and inner ears are composed of delicate mechanisms that are sensitive to injury or disease. Prompt and appropriate treatment is important to preserve your hearing.

Diagnosis of a ruptured or perforated eardrum

Your family doctor or ENT specialist can often determine if you have a perforated eardrum with a visual inspection using a lighted instrument (otoscope).

He or she may conduct or order additional tests to determine the cause of the rupture or degree of damage. These tests include:

• Laboratory tests. If there’s discharge from your ear, your doctor may order a laboratory test or culture to detect a bacterial infection of your middle ear.
• Tuning fork evaluation. Tuning forks are two-pronged, metal instruments that produce sounds when struck. Simple tests with tuning forks can help your doctor detect hearing loss. A tuning fork evaluation may also reveal whether hearing loss is caused by damage to the vibrating parts of your middle ear (including your eardrum), damage to sensors or nerves of your inner ear, or damage to both.
• Tympanometry. A tympanometer uses a device inserted into your ear canal that measures the response of your eardrum to slight changes in air pressure. Certain patterns of response can indicate a perforated eardrum.
• Audiology exam. If other hearing tests are inconclusive, your doctor may order a series of strictly calibrated tests conducted in a soundproof booth that measure how well you hear sounds at different volumes and pitches (audiology exam).

Treatment of a ruptured or perforated eardrum

Most perforated eardrums heal without treatment within a few weeks. Your doctor may prescribe antibiotic drops if there’s evidence of infection. If the tear or hole in your eardrum doesn’t heal by itself, treatment will involve procedures to close the perforation. These may include:

• Eardrum patch. If the tear or hole in your eardrum doesn’t close on its own, an ENT specialist may seal it with a patch. With this office procedure, your ENT doctor may apply a chemical to the edges of the tear to stimulate growth and then apply a patch over the hole. The procedure may need to be repeated more than once before the hole closes.
• Surgery. If a patch doesn’t result in proper healing or your ENT doctor determines that the tear isn’t likely to heal with a patch, he or she may recommend surgery. The most common surgical procedure is called tympanoplasty. Your surgeon grafts a tiny patch of your own tissue to close the hole in the eardrum. This procedure is done on an outpatient basis, meaning you can usually go home the same day unless medical anesthesia conditions require a longer hospital stay.

Home remedies for a ruptured or perforated eardrum

A ruptured eardrum usually heals on its own within weeks. In some cases, healing takes months. Until your doctor tells you that your ear is healed, protect it by doing the following:

• Keep your ear dry. Place a waterproof silicone earplug or cotton ball coated with petroleum jelly in your ear when showering or bathing.
• Refrain from cleaning your ears. Give your eardrum time to heal completely.
• Avoid blowing your nose. The pressure created when blowing your nose can damage your healing eardrum.

1. Ruptured eardrum (perforated eardrum). Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/ruptured-eardrum/symptoms-causes/syc-20351879[↩]

What is the sensory nervous system

The sensory nervous system is part of the peripheral nervous system.

The nervous system has two major anatomical subdivisions:

• The central nervous system (CNS) consists of the brain and spinal cord, which are enclosed and protected by the cranium and vertebral column. The central nervous system is discussed further in the other posts: Human brain and Spinal cord.

• The peripheral nervous system (PNS) consists of all the rest; it is composed of nerves and ganglia. A nerve is a bundle of nerve fibers (axons) wrapped in fibrous connective tissue. Nerves emerge from the central nervous system (brain and spinal cord) through foramina of the skull and vertebral column and carry signals to and from other organs of the body. A ganglion (plural, ganglia) is a knotlike swelling in a nerve where the cell bodies of peripheral neurons are concentrated.

The sensory (afferent) nervous system carries signals from various receptors (sense organs and simple sensory nerve endings) to the central nervous system (CNS). This pathway informs the central nervous system (the brain and the spinal cord) of stimuli within and around the body.

The sensory systems keep the central nervous system (the brain and the spinal cord) informed of changes in the external and internal environments. The sensory information is integrated and processed by interneurons in the spinal cord and brain. Responses to the integrative decisions are brought about by motor activities (muscular contractions and glandular secretions). The cerebral cortex, the outer part of the brain, plays a major role in controlling precise voluntary muscular movements. Other brain regions provide important integration for regulation of automatic movements.

Within the sensory division of the peripheral nervous system (PNS), sensory inputs are differentiated as general (widespread) or special (localized, i.e., the special senses).

Sensory receptor. The distal end of a sensory neuron (dendrite) or an associated sensory structure serves as a sensory receptor. It responds to a specific stimulus—a change in the internal or external environment—by producing a graded potential called a generator (or receptor) potential. If a generator potential reaches the threshold level of depolarization, it will trigger one or more nerve impulses in the sensory neuron.

Figure 1. Spinal cord segments

Figure 2. Processing of sensory input and motor output by the spinal cord

Note: Sensory input is conveyed from sensory receptors to the posterior gray horns of the spinal cord, and motor output is conveyed from the anterior and lateral gray horns of the spinal cord to effectors (muscles and glands).

Ascending Tracts

Ascending tracts carry sensory signals up the spinal cord. Sensory signals typically travel across three neurons from their origin in the receptors to their destination in the brain: a first-order neuron that detects a stimulus and transmits a signal to the spinal cord or brainstem; a second-order neuron that continues as far as a “gateway” called the thalamus at the upper end of the brainstem; and a third-order neuron that carries the signal the rest of the way to the cerebral cortex. The axons of these neurons are called the first- through third-order nerve fibers.

Figure 3. Locations of major sensory system shown in cross section of the spinal cord

Figure 4. Spinal cord ascending tracts to the brain

The major ascending tracts are as follows. The names of most of them consist of the prefix spino- followed by a root denoting the destination of its fibers in the brain, although this naming system does not apply to the first two.

Gracile fasciculus

The gracile fasciculus carries signals from the midthoracic and lower parts of the body. Below vertebra T6, it composes the entire posterior column. At T6, it is joined by the cuneate fasciculus, discussed next. It consists of first-order nerve fibers that travel up the ipsilateral side of the spinal cord and terminate at the gracile nucleus in the medulla oblongata of the brainstem. These fibers carry signals for vibration, visceral pain, deep and discriminative touch (touch whose location one can precisely identify), and especially proprioception from the lower limbs and lower trunk. Proprioception is the nonvisual sense of the position and movements of the body.

Cuneate fasciculus

The cuneate fasciculus joins the gracile fasciculus at the T6 level. It occupies the lateral portion of the posterior column and forces the gracile fasciculus medially. It carries the same type of sensory signals, originating from T6 and up (from the upper limbs and chest). Its fibers end in the cuneate nucleus on the ipsilateral side of the medulla oblongata. In the medulla, second-order fibers of the gracile and cuneate systems decussate and form the medial lemniscus, a tract of nerve fibers that leads the rest of the way up the brainstem to the thalamus. Third-order fibers go from the thalamus to the cerebral cortex. Because of decussation, the signals carried by the gracile and cuneate fasciculi ultimately go to the contralateral cerebral hemisphere.

Spinothalamic tract

The spinothalamic tract and some smaller tracts form the anterolateral system, which passes up the anterior and lateral columns of the spinal cord. The spinothalamic tract carries signals for pain, temperature, pressure, tickle, itch, and light or crude touch. Light touch is the sensation produced by stroking hairless skin with a feather or cotton wisp, without indenting the skin; crude touch is touch whose location one can only vaguely identify.

In this pathway, first-order neurons end in the posterior horn of the spinal cord near the point of entry. Here they synapse with second-order neurons, which decussate and form the contralateral ascending spinothalamic tract. These fibers lead all the way to the thalamus. Third-order neurons continue from there to the cerebral cortex. Because of decussation, sensory signals in this tract arrive in the cerebral hemisphere contralateral to their point of origin.

Spinoreticular tract

The spinoreticular tract also travels up the anterolateral system. It carries pain signals resulting from tissue injury. The first-order sensory neurons enter the posterior horn and immediately synapse with second-order neurons. These decussate to the opposite anterolateral system, ascend the cord, and end in a loosely organized core of gray matter called the reticular formation in the medulla and pons. Third-order neurons continue from the pons to the thalamus, and fourth-order neurons complete the path from there to the cerebral cortex.

Posterior and anterior spinocerebellar tracts

The posterior and anterior spinocerebellar tracts travel through the lateral column and carry proprioceptive signals from the limbs and trunk to the cerebellum at the rear of the brain. Their first-order neurons originate in muscles and tendons and end in the posterior horn of the spinal cord. Second-order neurons send  their fibers up the spinocerebellar tracts and end in the cerebellum.

Fibers of the posterior tract travel up the ipsilateral side of the spinal cord. Those of the anterior tract cross over and travel up the contralateral side but then cross back in the brainstem to enter the ipsilateral side of the cerebellum. Both tracts provide the cerebellum with feedback needed to coordinate muscle action.

Figure 5. Rami of the spinal nerve

Figure 6. Spinal nerve fiber anatomy

Peripheral Sensory System Organs and Receptors

Peripheral sensory receptors are structures that pick up sensory stimuli and then initiate signals in the sensory axons. Most receptors fit into two main categories:

1. Free nerve endings of sensory neurons and
2. Complete receptor cells, which are specialized epithelial cells or small neurons that transfer sensory information to sensory neurons. Free nerve endings monitor most types of general sensory information (such as touch, pain, pressure, temperature, and proprioception), whereas specialized receptor cells monitor most types of special sensory information (taste, vision, hearing, and equilibrium).

Sensory receptors may be categorized based on either function or structure.

Figure 7. Structure of free and encapsulated general sensory receptors

Sensory Receptors Functional Classification

Functional classifications group receptors according to their location or the type of stimulus they detect.

Location of Receptors

Sensory receptors monitor both the external and the internal environment. Sensory receptors can be described by their location in the body or the location of the stimuli to which they respond.

• Exteroceptors are sensitive to stimuli arising outside the body. Accordingly, most exteroceptors are located at or near the body surface and include receptors for touch, pressure, pain, and temperature in the skin and most receptors of the special sense organs.
• Interoceptors also called visceroceptors, receive stimuli from the internal viscera, such as the digestive tube, bladder, and lungs. Different interoceptors monitor a variety of stimuli, including changes in chemical concentration, taste stimuli, the stretching of tissues, and temperature. Their activation causes us to feel visceral pain, nausea, hunger, or fullness.
• Proprioceptors are located in the musculoskeletal organs, such as skeletal muscles, tendons, joints, and ligaments. Proprioceptors monitor the degree of stretch of these locomotory organs and send input on body movements to the CNS (brain and spinal cord).

Stimulus Type

Sensory receptors monitor many types of stimuli. The type of stimulus that most readily activates a sensory receptor can be used to categorize it functionally.

• Mechanoreceptors respond to mechanical forces such as touch, pressure, stretch, and vibrations. One type of mechanoreceptor, called a baroreceptor, monitors blood pressure.
• Thermoreceptors respond to temperature changes.
• Chemoreceptors respond to chemicals in solution (such as molecules tasted or smelled) and to changes in blood chemistry.
• Photoreceptors in the eye respond to light.
• Nociceptors respond to harmful stimuli that result in pain.

Sensory Receptors Structural Classification

This section considers only the general sensory receptors. All these widely distributed receptors are nerve endings of sensory neurons that monitor touch, pressure, vibration, stretch, pain, temperature, and proprioception.

Structurally, sensory receptors are divided into two broad groups:

1. Free nerve endings and
2. Encapsulated nerve endings surrounded by a capsule of connective tissue.

It is important to remember that there is no one to-one correspondence between structural type and stimulus detected. Each type of receptor can respond to several different kinds of stimuli. In addition, similar stimuli can activate different types of receptors.

Figure 8. Sensory receptors free nerve endings

Free Nerve Endings

Free nerve endings of sensory neurons invade almost all tissues of the body but are particularly abundant in epithelia and in the connective tissue that underlies epithelia. These receptors are primarily nociceptors and thermoreceptors, responding to pain and temperature (though some respond to tissue movements caused by pressure). One way to characterize free nerve endings functionally is to say that they monitor the affective senses, those to which people have an emotional response—and people certainly respond emotionally to pain!

Itch receptors consist of free nerve endings in the dermis. Itch receptors are activated by chemicals present at inflamed sites, such as histamine.

Certain free nerve endings contribute to epithelial tactile complexes (Merkel discs), which lie in the epidermis of the skin. Each consists of a disc-shaped tactile epithelial cell innervated by a sensory nerve ending. These complexes are slowly adapting mechanoreceptors for light touch; that is, they continue to respond and send out action potentials even after a long period of continual stimulation.

Hair follicle receptors, free nerve endings that wrap around hair follicles, are mechanoreceptors for light touch that monitor the bending of hairs. Unlike epithelial tactile complexes, they are rapidly adapting, meaning that the sensation disappears quickly even if the stimulus is maintained. The tickle of a mosquito landing on your forearm is mediated by hair follicle receptors.

Encapsulated Nerve Endings

All encapsulated nerve endings consist of one or more end fibers of sensory neurons enclosed in a capsule of connective tissue. All seem to be mechanoreceptors, and their capsules serve either to amplify the stimulus or to filter out the wrong types of stimuli. Encapsulated receptors vary widely in shape, size, and distribution in the body. The main types are tactile (Meissner’s) corpuscles, lamellar (Pacinian) corpuscles, bulbous corpuscles (Ruffini endings) and proprioceptors.

Tactile Corpuscles

In a tactile corpuscle (Meissner’s corpuscle), a few spiraling nerve endings are surrounded by Schwann cells, which in turn are surrounded by an eggshaped capsule of connective tissue. These corpuscles, which occur in the dermal papillae beneath the epidermis, are rapidly adapting receptors for fine, discriminative touch. They mainly occur in sensitive and hairless areas of the skin, such as the soles, palms, fingertips, nipples, and lips. Tactile corpuscles perform the same “light touch” function in hairless skin that hair follicle receptors perform in hairy skin.

Lamellar Corpuscles

Scattered throughout the deep connective tissues of the body are lamellar corpuscles (Pacinian corpuscles). They occur, for example, in the hypodermis deep to the skin. Although they are sensitive to deep pressure, they respond only to the initial application of that pressure before they tire and stop firing. Therefore, lamellar corpuscles are rapidly adapting receptors that are best suited to monitor vibration, an on/off pressure stimulus.

These corpuscles are large enough to be visible to the unaided eye—about 0.5–1 mm wide and 1–2 mm long. In section, a lamellar corpuscle resembles a cut onion: Its single nerve ending is surrounded by up to 60 layers of flattened Schwann cells, which in turn are covered by a capsule of connective tissue.

Bulbous Corpuscles

Located in the dermis and elsewhere are bulbous corpuscles (Ruffini endings), which contain an array of nerve endings enclosed in a thin, flattened capsule. Like lamellar corpuscles, they respond to pressure and touch. However, they adapt slowly and thus can monitor continuous pressure placed on the skin.

Proprioceptors

Virtually all proprioceptors are encapsulated nerve endings that monitor stretch in the locomotory organs. Proprioceptors include muscle spindles, tendon organs, and joint kinesthetic receptors.

Figure 9. Proprioceptors – muscle spindle

Muscle spindles (neuromuscular spindles) measure the changing length of a muscle as that muscle contracts and is stretched back to its original length. An average muscle contains some 50 to 100 muscle spindles, which are embedded in the perimysium between the fascicles. Structurally, each spindle contains several modified skeletal muscle fibers called intrafusal muscle fibers (intra = within; fusal = the spindle) surrounded by a connective tissue capsule.

Intrafusal muscle fibers have fewer striations than the extrafusal (extra = outside) muscle fibers, that is, the ordinary muscle cells outside the spindles. The intrafusal fibers are innervated by two types of sensory endings: Anulospiral endings, or primary sensory endings, twirl around the noncontractile middle of the intrafusal fibers innervating the spindle center. These receptors are stimulated by the rate and degree of stretch of the muscle spindle. Secondary sensory endings called flower spray endings, monitor the spindle ends (the only contractile parts of the spindle) and respond only to degree of stretch.

Muscles are stretched by the contraction of antagonist muscles and also by the movements that occur as a person begins to lose balance. The muscle spindles sense this lengthening in the following way:

• When a whole muscle is stretched, its intrafusal fibers are also stretched. This stretching activates the primary and secondary sensory endings that innervate the spindle, causing them to fire off impulses to the spinal cord and brain.
• The CNS (brain and spinal cord) then activates spinal motor neurons called A (alpha) efferent neurons that cause the entire muscle (extrafusal fibers) to generate contractile force and resist further stretching. This response can be initiated by a monosynaptic spinal reflex that rapidly prevents a fall;  alternatively, the response can be controlled by the cerebellum regulating muscle tone, the steady force generated by noncontracting muscles to resist stretching.

Also innervating the intrafusal fibers of the muscle spindle are spinal motor neurons called G (gamma) efferent neurons. These neurons preset the sensitivity of the spindle to stretch. When the brain stimulates the gamma motor neurons to fire, the intrafusal muscle fibers contract and become tense so that very little stretch is needed to stimulate the sensory endings, making the spindles highly sensitive to applied stretch. Gamma motor neurons are most active when balance reflexes must be razor sharp, as for a gymnast on a balance beam or a rock climber on a vertical face.

Tendon organs (Golgi tendon organs) are proprioceptors located near the muscle-tendon junction, where they monitor tension within tendons. Each consists of an encapsulated bundle of tendon fibers (collagen fibers) within which sensory nerve endings are intertwined. When a contracting muscle pulls on its tendon, tendon organs are stimulated, and their sensory neurons send this information to the cerebellum. These receptors also induce a spinal reflex that both relaxes the contracting muscle and activates its antagonist. This relaxation reflex is important in motor activities that involve rapid alternation between flexion and extension, such as running.

Joint kinesthetic receptors (movement feeling) are proprioceptors that monitor stretch in the synovial joints. Specifically, they are sensory nerve endings within the joint capsules. Four types of joint kinesthetic receptors are present within each joint capsule:

1. Lamellar (Pacinian) corpuscles: These rapidly adapting stretch receptors are ideal for measuring acceleration and rapid movement of the joints.
2. Bulbous corpuscles (Ruffini endings): These slowly adapting stretch receptors are ideal for measuring the positions of nonmoving joints and the stretch of joints that undergo slow, sustained movements.
3. Free nerve endings: May be pain receptors.
4. Receptors resembling tendon organs: Their function in joints is not known.

Joint receptors, like the other two classes of proprioceptors, send information on body movements to the cerebellum and cerebrum, as well as to spinal reflex arcs.

The nervous system

The nervous system has two major anatomical subdivisions:

• The central nervous system (CNS) consists of the brain and spinal cord, which are enclosed and protected by the cranium and vertebral column. The central nervous system is discussed further in the other posts: Human brain and Spinal cord.

• The peripheral nervous system (PNS) consists of all the rest; it is composed of nerves and ganglia. A nerve is a bundle of nerve fibers (axons) wrapped in fibrous connective tissue. Nerves emerge from the central nervous system (CNS) through foramina of the skull and vertebral column and carry signals to and from other organs of the body. A ganglion (plural, ganglia) is a knotlike swelling in a nerve where the cell bodies of peripheral neurons are concentrated.

Figure 1. Nervous system and its parts

Peripheral nervous system

The peripheral nervous system is functionally divided into sensory and motor divisions, and each of these is further divided into somatic and visceral subdivisions.

The sensory (afferent) division carries signals from various receptors (sense organs and simple sensory nerve endings) to the central nervous system (CNS). This pathway informs the central nervous system (CNS) of stimuli within and around the body.

• The somatic sensory division carries signals from receptors in the skin, muscles, bones, and joints.

• The visceral sensory division carries signals mainly from the viscera of the thoracic and abdominal cavities, such as the heart, lungs, stomach, and urinary bladder.

The motor (efferent) division carries signals from the CNS (the brain and the spinal cord) mainly to gland and muscle cells that carry out the body’s responses. Cells and organs that respond to these signals are called effectors.

• The somatic motor division carries signals to the skeletal muscles. This produces voluntary muscle contractions as well as involuntary somatic reflexes.

• The visceral motor division (autonomic nervous system) carries signals to glands, cardiac muscle, and smooth muscle. You usually have no voluntary control over these effectors, and the autonomic nervous system operates at an unconscious level. The responses of the autonomic nervous system and its effectors are visceral reflexes. The autonomic nervous system has two further divisions:
  • The sympathetic division tends to arouse the body for action—for example, by accelerating the heartbeat and increasing respiratory airflow—but it inhibits digestion.
  • The parasympathetic division tends to have a calming effect—slowing the heartbeat, for example—but it stimulates digestion.

Nervous system function

The communicative role of the nervous system is carried out by nerve cells, or neurons. These cells have three fundamental physiological properties that enable them to communicate with other cells:

1. Excitability. All cells are excitable—that is, they respond to environmental changes (stimuli). Neurons exhibit this property to the highest degree.
2. Conductivity. Neurons respond to stimuli by producing electrical signals that are quickly conducted to other cells at distant locations.
3. Secretion. When the signal reaches the end of a nerve fiber, the neuron secretes a neurotransmitter that crosses the gap and stimulates the next cell.

Functional Classes of Neurons

There are three general classes of neurons corresponding to the three major aspects of nervous system function listed above (e.g. excitability, conductivity and secretion):

1. Sensory (afferent) neurons are specialized to detect stimuli such as light, heat, pressure, and chemicals, and transmit information about them to the central nervous system (CNS). Such neurons begin in almost every organ of the body and end in the central nervous system (CNS); the word afferent refers to signal conduction toward the central nervous system (CNS). Some receptors, such as those for pain and smell, are themselves neurons. In other cases, such as taste and hearing, the receptor is a separate cell that communicates directly with a sensory neuron.
2. Interneurons lie entirely within the central nervous system (CNS). They receive signals from many other neurons and carry out the integrative function of the nervous system—that is, they process, store, and retrieve information and “make decisions” that determine how the body responds to stimuli. About 90% of our neurons are interneurons. The word interneuron refers to the fact that they lie between, and interconnect, the incoming sensory pathways and the outgoing motor pathways of the central nervous system (CNS).
3. Motor (efferent) neurons send signals predominantly to muscle and gland cells, the effectors. They are called motor neurons because most of them lead to muscle cells, and efferent neurons to signify signal conduction away from the central nervous system (CNS).

Figure 2. Functional classes of neurons

Structure of a Neuron

There are several varieties of neurons, but a good starting point for discussion is a motor neuron of the spinal cord. The control center of the neuron is the neurosoma, also called the soma or cell body. It has a centrally located nucleus with a large nucleolus. The cytoplasm contains mitochondria, lysosomes, a Golgi complex, numerous inclusions, and an extensive rough endoplasmic reticulum and cytoskeleton. The cytoskeleton consists of a dense mesh of microtubules and neurofibrils (bundles of actin filaments), which compartmentalize the rough endoplasmic reticulum into darkstaining regions called chromatophilic substance. This is unique to neurons and a helpful clue to identifying them in tissue sections with mixed cell types. Mature neurons have no centrioles and cannot undergo any further mitosis after adolescence. Consequently, neurons that die are usually irreplaceable; surviving neurons cannot multiply to replace those lost. However, neurons are unusually long-lived cells, capable of functioning for over a hundred years. But even in old age, there are unspecialized stem cells in some parts of the central nervous system (CNS) that can divide and regenerate nervous tissue to a limited extent.

The major inclusions in a neuron are glycogen granules, lipid droplets, melanin, and a golden brown pigment called lipofuscin, produced when lysosomes degrade worn-out organelles and other products. Lipofuscin accumulates with age and pushes the nucleus to one side of the cell. Lipofuscin granules are also called “wear-and-tear granules” because they are most abundant in old neurons. They seem harmless to neuron function.

Figure 3. General structure of a neuron

The somas of most neurons give rise to a few thick processes that branch into a vast number of dendrites—named for their striking resemblance to the bare branches of a tree in winter. Dendrites are the primary site for receiving signals from other neurons. Some neurons have only one dendrite and some have thousands. The more dendrites a neuron has, the more information it can receive and incorporate into its decision making. As tangled as the dendrites may seem, they provide exquisitely precise pathways for the reception and processing of neural information.

On one side of the neurosoma is a mound called the axon hillock, from which the axon (nerve fiber) originates. The axon is cylindrical and relatively unbranched for most of its length, although it may give rise to a few branches called axon collaterals near the soma, and most axons branch extensively at their distal end. An axon is specialized for rapid conduction of nerve signals to points remote from the soma. Its cytoplasm is called the axoplasm and its membrane the axolemma. A neuron never has more than one axon, and some neurons have none.

Somas range from 5 to 135 μm in diameter, and axons from 1 to 20 μm in diameter and from a few millimeters to more than a meter long. Such dimensions are more impressive when you scale them up to the size of familiar objects. If the soma of a spinal motor neuron were the size of a tennis ball, its dendrites would form a dense bushy mass that could fill a 30-seat classroom from floor to ceiling. Its axon would be up to a mile long but a little narrower than a garden hose. The neuron must assemble molecules and organelles in its “tennis ball” soma and deliver them through its “mile-long garden hose” to the end of the axon.

At the distal end, an axon usually has a terminal arborization—an extensive complex of fine branches. Each branch ends in a bulbous axon terminal (terminal button), which forms a junction (synapse) with the next cell. It contains synaptic vesicles full of neurotransmitter. In autonomic neurons, however, the axon has numerous beads called varicosities along its length. Each varicosity contains synaptic vesicles and secretes neurotransmitter.

Not all neurons fit the preceding description. Neurons are classified structurally according to the number of processes extending from the soma:

• Multipolar neurons are those, like the preceding, that have one axon and multiple dendrites. This is the most common type and includes most neurons of the brain and spinal cord.
• Bipolar neurons have one axon and one dendrite. Examples include olfactory cells of the nose, certain neurons of the retina, and sensory neurons of the ear.
• Unipolar neurons have only a single process leading away from the soma. They are represented by the neurons that carry signals to the spinal cord for such senses as touch and pain. They are also called pseudounipolar because they start out as bipolar neurons in the embryo, but their two processes fuse into one as the neuron matures. A short distance away from the soma, the process branches like a T into a peripheral fiber and a central fiber. The peripheral fiber begins with a sensory ending often far away from the soma—in the skin, for example. Its signals travel toward the soma, but bypass it and continue along the central fiber for a short remaining distance to the spinal cord. The dendrites are considered to be only the short receptive endings. The rest of the process, both peripheral and central, is the axon, defined by the presence of myelin and the ability to generate action potentials.
• Anaxonic neurons have multiple dendrites but no axon. They communicate locally through their dendrites and do not produce action potentials. Some anaxonic neurons are found in the brain, retina, and adrenal medulla. In the retina, they help in visual processes such as the perception of contrast.

Figure 4. Variation in Neuron Structure

Note:

Top panel, left to right: Two multipolar neurons of the brain—a pyramidal cell and a Purkinje cell.

Second panel, left to right: Two bipolar neurons—a bipolar cell of the retina and an olfactory neuron.

Third panel: A unipolar neuron of the type involved in the senses of touch and pain.

Bottom panel: An anaxonic neuron (amacrine cell) of the retina.

Axonal Transport

All of the proteins needed by a neuron must be made in the soma, where the protein-synthesizing organelles such as the nucleus, ribosomes, and rough endoplasmic reticulum are located. Yet many of these proteins are needed in the axon, for example to repair and maintain the axolemma, to serve as ion channels in the membrane, or to act in the axon terminal as enzymes and signaling molecules. Other substances are transported from the axon terminals back to the soma for disposal or recycling. The two-way passage of proteins, organelles, and other materials along an axon is called axonal transport. Movement away from the soma down the axon is called anterograde transport and movement up the axon toward the soma is called retrograde transport.

Materials travel along axonal microtubules that act like monorail tracks to guide them to their destination. But what is the “engine” that drives them along the tracks ? Anterograde transport employs a motor protein called kinesin and retrograde transport uses one called dynein (the same protein responsible for the motility of cilia and flagella). These proteins carry materials “on their backs” while they reach out, like the myosin heads of muscle, to bind repeatedly to the microtubules and walk along them.

There are two types of axonal transport: fast and slow.

1. Fast axonal transport occurs at a rate of 200 to 400 mm/day and may be either anterograde or retrograde:
   + Fast anterograde transport moves mitochondria; synaptic vesicles; other organelles; components of the axolemma; calcium ions; enzymes such as acetylcholinesterase; and small molecules such as glucose, amino acids, and nucleotides toward the distal end of the axon.
   + Fast retrograde transport returns used synaptic vesicles and other materials to the soma and informs the soma of conditions at the axon terminals. Some pathogens exploit this process to invade the nervous system. They enter the distal tips of an axon and travel to the soma by retrograde transport. Examples include tetanus toxin and the herpes simplex, rabies, and polio viruses. In such infections, the delay between infection and the onset of symptoms corresponds to the time needed for the pathogens to reach the somas.
2. Slow axonal transport is an anterograde process that works in a stop-and-go fashion. If you compare fast axonal transport to an express train traveling nonstop to its destination, slow axonal transport is like a local train that stops at every station. When moving, it goes just as fast as the express train, but the frequent stops result in an overall progress of only 0.2 to 0.5 mm/day. It moves enzymes and cytoskeletal components down the axon, renews worn-out axoplasmic components in mature neurons, and supplies new axoplasm for developing or regenerating neurons. Damaged nerves regenerate at a speed governed by slow axonal transport.

Supportive Cells (Neuroglia)

There are about a trillion (1,000,000,000,000 or 10¹²) neurons in the nervous system. Because they branch so extensively, they make up about 50% of the volume of the nervous tissue. Yet they are outnumbered at least 10 to 1 by cells called neuroglia or glial cells. Glial cells protect the neurons and help them function.

The word glia, which means “glue,” implies one of their roles—to bind neurons together and provide a supportive framework for the nervous tissue. In the fetus, they form a scaffold that guides young migrating neurons to their destinations. Wherever a mature neuron is not in synaptic contact with another cell, it is covered with glial cells. This prevents neurons from contacting each other except at points specialized for signal transmission, thus giving precision to their conduction pathways.

Figure 5. Neuroglia of the Central Nervous System

Types of Neuroglia

There are six kinds of neuroglia, each with a unique function. The first four types occur only in the central nervous system (brain and spinal cord):

1. Oligodendrocytes somewhat resemble an octopus; they have a bulbous body with as many as 15 arms. Each arm reaches out to a nerve fiber and spirals around it like electrical tape wrapped repeatedly around a wire. This wrapping, called the myelin sheath, insulates the nerve fiber from the extracellular fluid. It speeds up signal conduction in the nerve fiber.
2. Ependymal resemble a cuboidal epithelium lining the internal cavities of the brain and spinal cord. Unlike true epithelial cells, however, they have no  basement membrane and they exhibit rootlike processes that penetrate into the underlying tissue. Ependymal cells produce cerebrospinal fluid (CSF), a liquid that bathes the central nervous system (brain and spinal cord) and fills its internal cavities. They have patches of cilia on their apical surfaces that help to circulate the cerebrospinal fluid.
3. Microglia are small macrophages that develop from white blood cells called monocytes. They wander through the central nervous system (brain and spinal cord), putting out fingerlike extensions to constantly probe the tissue for cellular debris or other problems. They are thought to perform a complete checkup on the brain tissue several times a day, phagocytizing dead tissue, microorganisms, and other foreign matter. They become concentrated in areas damaged by infection, trauma, or stroke. Pathologists look for clusters of microglia in brain tissue as a clue to sites of injury. Microglia also aid in synaptic remodeling, changing the connections between neurons.
4. Astrocytes are the most abundant glial cells in the central nervous system (brain and spinal cord) and constitute over 90% of the tissue in some areas of the brain. They cover the entire brain surface and most nonsynaptic regions of the neurons in the gray matter. They are named for their many-branched, somewhat starlike shape. They have the most diverse functions of any glia:

• + They form a supportive framework for the nervous tissue.
• + They have extensions called perivascular feet, which contact the blood capillaries and stimulate them to form a tight, protective seal called the blood–brain barrier.
• + They monitor neuron activity, stimulate dilation and constriction of blood vessels, and thus regulate blood flow in the brain tissue to meet changing needs for oxygen and nutrients.
• + They convert blood glucose to lactate and supply this to the neurons for nourishment.
• + They secrete nerve growth factors that regulate nerve development.
• + They communicate electrically with neurons and influence synaptic signaling between them.
• + They regulate the composition of the tissue fluid. When neurons transmit signals, they release neurotransmitters and potassium ions. Astrocytes absorb these and prevent them from reaching excessive levels in the tissue fluid.
• + When neurons are damaged, astrocytes form hardened scar tissue and fill space formerly occupied by the neurons. This process is called astrocytosis or sclerosis.

The other two types of glial cells occur only in the peripheral nervous system:

1. Schwann cells or neurilemmocytes, envelop nerve fibers of the peripheral nervous system. In most cases, a Schwann cell winds repeatedly around a nerve fiber and produces a myelin sheath similar to the one produced by oligodendrocytes in the central nervous system (brain and spinal cord). There are some important differences in myelin production between the central nervous system (brain and spinal cord) and peripheral nervous system, which we consider shortly. Schwann cells also assist in the regeneration of damaged fibers, as described later.
2. Satellite cells surround the somas in ganglia of the peripheral nervous system. They provide insulation around the soma and regulate the chemical environment of the neurons.

Myelin

The myelin sheath is a spiral layer of insulation around a nerve fiber, formed by oligodendrocytes in the central nervous system (brain and spinal cord) and Schwann cells in the peripheral nervous system. Since it consists of the plasma membranes of glial cells, its composition is like that of plasma membranes in general. It is about 20% protein and 80% lipid, the latter including phospholipids, glycolipids, and cholesterol.

Production of the myelin sheath is called myelination. It begins in the fourteenth week of fetal development, yet hardly any myelin exists in the brain at the time of birth. Myelination proceeds rapidly in infancy and isn’t completed until late adolescence. Since myelin has such a high lipid content, dietary fat is important to early nervous system development. It is best not to give children under 2 years old the sort of low-fat diets (skimmed milk, etc.) that may be beneficial to an adult.

Figure 6. Myelination

Note: (a) A Schwann cell of the peripheral nervous system, wrapping repeatedly around an axon to form the multilayered myelin sheath.
The myelin spirals outward away from the axon as it is laid down.

(b) An oligodendrocyte of the central nervous system (brain and spinal cord) wrapping around the axons of multiple neurons. Here, the myelin spirals inward toward the axon as it is laid down.

(c) A myelinated axon (top) and unmyelinated axon (bottom).

In the peripheral nervous system, a Schwann cell spirals repeatedly around a single nerve fiber, laying down up to 100 compact layers of its own membrane with almost no cytoplasm between the membranes. These layers constitute the myelin sheath. The Schwann cell spirals outward as it wraps the nerve fiber, finally ending with a thick outermost coil called the neurilemma. Here, the bulging body of the Schwann cell contains its nucleus and most of its cytoplasm. External to the neurilemma is a basal lamina and then a thin sleeve of fibrous connective tissue called the endoneurium. To visualize this myelination process, imagine that you wrap an almost-empty tube of toothpaste tightly around a pencil. The pencil represents the axon, and the spiral layers of toothpaste tube represent the myelin. The toothpaste, like the cytoplasm of the cell, would be forced to one end of the tube and form a bulge on the external surface of the wrapping, like the body of the Schwann cell.

In the central nervous system (brain and spinal cord), each oligodendrocyte reaches out to myelinate several nerve fibers in its immediate vicinity. Since it is anchored to multiple nerve fibers, it cannot migrate around any one of them like a Schwann cell does. It must push newer layers of myelin under the older ones, so myelination spirals inward toward the nerve fiber. Nerve fibers of the central nervous system (brain and spinal cord) have no neurilemma or endoneurium. The contrasting modes of myelination are called centrifugal myelination (“away from the center”) in the peripheral nervous system and centripetal myelination (“toward the center”) in the central nervous system (brain and spinal cord).

In both the peripheral nervous system and central nervous system (brain and spinal cord), a nerve fiber is much longer than the reach of a single glial cell, so it requires many Schwann cells or oligodendrocytes to cover one nerve fiber. Consequently, the myelin sheath is segmented. Each gap between segments is called a node of Ranvier or myelin sheath gap; the myelin-covered segments from each node to the next are called internodes. The internodes are about 0.2 to 1.0 mm long. The short section of nerve fiber between the axon hillock and the first glial cell is called the initial segment. Since the axon hillock and initial segment play an important role in initiating a nerve signal, they are collectively called the trigger zone.

Unmyelinated Nerve Fibers

Many nerve fibers in the peripheral nervous system and central nervous system (brain and spinal cord) are unmyelinated. In the peripheral nervous system, however, even the unmyelinated fibers are enveloped in Schwann cells. In this case, one Schwann cell harbors from 1 to 12 small nerve fibers in grooves in its surface. The Schwann cell’s plasma membrane does not spiral repeatedly around the fiber as it does in a myelin sheath, but folds once around each fiber and may somewhat overlap itself along the edges. This wrapping is the neurilemma. Most nerve fibers travel through individual channels in the Schwann cell, but small fibers are sometimes bundled together within a single channel. A basal lamina surrounds the entire Schwann cell along with its nerve fibers.

Figure 7. Unmyelinated nerve fibers

Conduction Speed of Nerve Fibers

The speed at which a nerve signal travels along a nerve fiber depends on two factors: the diameter of the fiber and the presence or absence of myelin. Signal conduction occurs along the surface of a fiber, not deep within its axoplasm. Large fibers have more surface area and conduct signals more rapidly than small fibers.

Myelin further speeds signal conduction. Nerve signals travel about 0.5 to 2.0 m/s in small unmyelinated fibers (2–4 μm in diameter); 3 to 15 m/s in myelinated fibers of the same size; and as fast as 120 m/s in large myelinated fibers (up to 20 μm in diameter). You might wonder why all of your nerve fibers are not large, myelinated, and fast; but if this were so, your nervous system would be impossibly bulky or limited to far fewer fibers. Large nerve fibers require large somas and a large expenditure of energy to maintain them. The evolution of myelin allowed for the subsequent evolution of more complex and responsive nervous systems with smaller, more energy-efficient neurons. Slow unmyelinated fibers are quite sufficient for processes in which quick responses are not particularly important, such as secreting stomach acid or dilating the pupil. Fast myelinated fibers are employed where speed is more important, as in motor commands to the skeletal muscles and sensory signals for vision and balance.

Nerve Regeneration

Nerve fibers of the peripheral nervous system are vulnerable to cuts, crushing injuries, and other trauma. A damaged peripheral nerve fiber may regenerate, however, if its soma is intact and at least some neurilemma remains. Figure 8 shows the process of regeneration, taking as its example a somatic motor neuron:

Figure 8. Regeneration of a Damaged Nerve Fiber

1. In the normal nerve fiber, note the size of the soma and the size of the muscle fibers for comparison to later stages.
2. When a nerve fiber is cut, the fiber distal to the injury cannot survive because it is incapable of protein synthesis. Protein-synthesizing organelles are mostly in the soma. As the distal fiber degenerates, so do its Schwann cells, which depend on it for their maintenance. Macrophages clean up tissue debris at the point of injury and beyond.
3. The soma exhibits a number of abnormalities of its own, probably because it is cut off from the supply of nerve growth factors from the neuron’s target cells. The soma swells, the endoplasmic reticulum breaks up (so the chromatophilic substance disperses), and the nucleus moves off center. Not all damaged neurons survive; some die at this stage. But often, the axon stump sprouts multiple growth processes as the severed distal end shows continued degeneration of its axon and Schwann cells. Muscle fibers deprived of their nerve supply exhibit a shrinkage called denervation atrophy.
4. Near the injury, Schwann cells, the basal lamina, and the neurilemma form a regeneration tube. The Schwann cells produce cell-adhesion molecules and nerve growth factors that enable a neuron to regrow to its original destination. When one growth process finds its way into the tube, it grows rapidly (3–5 mm/day), and the other growth processes are retracted.
5. The regeneration tube guides the growing sprout back to the original target cells, reestablishing synaptic contact.
6. When contact is established, the soma shrinks and returns to its original appearance, and the reinnervated muscle fibers regrow. Regeneration is not perfect. Some nerve fibers connect to the wrong muscle fibers or never find a muscle fiber at all, and some damaged motor neurons simply die. Nerve injury is therefore often followed by some degree of functional deficit. Even when regeneration is achieved, the slow rate of axon regrowth means that some nerve function may take as long as 2 years to recover. Schwann cells and endoneurium are required for nerve fiber regeneration. Both of these are lacking from the central nervous system (brain and spinal cord), so damaged central nervous system (brain and spinal cord) nerve fibers cannot regenerate at all. However, since the central nervous system (brain and spinal cord) is encased in bone, it suffers less trauma than the peripheral nerves.

Nervous system diseases

There are more than 600 neurologic diseases ¹. Major types include:

• Diseases caused by faulty genes, such as Huntington’s disease and muscular dystrophy
• Problems with the way the nervous system develops, such as spina bifida
• Degenerative diseases, where nerve cells are damaged or die, such as Parkinson’s disease and Alzheimer’s disease
• Diseases of the blood vessels that supply the brain, such as stroke
• Injuries to the spinal cord and brain
• Seizure disorders, such as epilepsy
• Cancer, such as brain tumors
• Infections, such as meningitis.

Alzheimer’s disease

Alzheimer’s disease is the most common form of dementia among older people ². Dementia is a brain disorder that seriously affects a person’s ability to carry out daily activities. Alzheimer’s disease is the fourth leading cause of death in adults ³. The incidence of the disease rises steeply with age. Alzheimer’s disease is twice as common in women than in men.

Alzheimer’s disease tends to run in families; currently, mutations in four genes, situated on chromosomes 1, 14, 19, and 21, are believed to play a role in the disease ³.

Alzheimer’s disease begins slowly. It first involves the parts of the brain that control thought, memory and language. People with Alzheimer’s disease may have trouble remembering things that happened recently or names of people they know. A related problem, mild cognitive impairment, causes more memory problems than normal for people of the same age. Many, but not all, people with mild cognitive impairment will develop Alzheimer’s disease.

In Alzheimer’s disease, over time, symptoms get worse. People may not recognize family members. They may have trouble speaking, reading or writing. They may forget how to brush their teeth or comb their hair. Later on, they may become anxious or aggressive, or wander away from home. Eventually, they need total care. This can cause great stress for family members who must care for them.

Alzheimer’s disease usually begins after age 60. The risk goes up as you get older. Your risk is also higher if a family member has had the disease.

No treatment can stop the disease. However, some drugs may help keep symptoms from getting worse for a limited time.

Epilepsy

Epilepsy is a brain disorder that causes people to have recurring seizures ⁴. The seizures happen when clusters of nerve cells, or neurons, in the brain send out the wrong signals. People may have strange sensations and emotions or behave strangely. They may have violent muscle spasms or lose consciousness.

Epilepsy affects approximately 1% of the population making it one of the most common neurological diseases ⁵. Epilepsy can strike at any time of life—from infancy to old age. There are many forms of epilepsy—most are rare. While epilepsy varies widely in type and severity, all forms of this disorder are characterized by recurring seizures resulting from abnormal cell firing in the brain. In approximately 30% of cases, epilepsy is caused by such events as head trauma, tumor, stroke, or infection. In those cases for which there is no known cause, recent evidence suggests there may be genetic predisposition to developing the disease.

Epilepsy has many possible causes, including illness, brain injury, and abnormal brain development. In many cases, the cause is unknown. But to date, at least twelve forms of epilepsy have been demonstrated to possess some genetic basis ⁵.

Doctors use brain scans and other tests to diagnose epilepsy. It is important to start treatment right away. There is no cure for epilepsy, but medicines can control seizures for most people. When medicines are not working well, surgery or implanted devices such as vagus nerve stimulators may help. Special diets can help some children with epilepsy.

Huntington’s disease

Huntington disease is an inherited, degenerative neurological disease that leads to dementia ⁶. Huntington’s disease causes certain nerve cells in the brain to waste away. People are born with the defective gene, but symptoms usually don’t appear until middle age. Early symptoms of Huntington’s disease may include uncontrolled movements, clumsiness, and balance problems. Later, Huntington’s disease can take away the ability to walk, talk, and swallow. Some people stop recognizing family members. Others are aware of their environment and are able to express emotions.

About 30,000 Americans have Huntington disease and about 150,000 more are at risk of inheriting the disease from a parent.

The Huntington disease gene, whose mutation results in Huntington disease, was mapped to chromosome 4 in 1983. The mutation is a characteristic expansion of a nucleotide triplet repeat in the DNA that codes for the protein huntingtin. As the number of repeated triplets – CAG (cytosine, adenine, guanine) – increases, the age of onset in the patient decreases. Furthermore, because the unstable trinucleotide repeat can lengthen when passed from parent to child, the age of onset can decrease from one generation to the next. Since people who have those repeats always suffer from Huntington disease, it suggests that the mutation causes a gain-of-function, in which the mRNA or protein takes on a new property or is expressed inappropriately.

If one of your parents has Huntington’s disease, you have a 50 percent chance of getting it. A blood test can tell you if have the Huntington’s disease gene and will develop the disease. Genetic counseling can help you weigh the risks and benefits of taking the test.

There is no cure. Medicines can help manage some of the symptoms, but cannot slow down or stop the disease.

Meningitis

Meningitis is inflammation of the thin tissue that surrounds the brain and spinal cord, called the meninges ⁷. There are several types of meningitis. The most common is viral meningitis. You get it when a virus enters the body through the nose or mouth and travels to the brain. Viral meningitis is almost never life-threatening and viruses rarely cause septicaemia ⁸. Bacterial meningitis is rare, but can be deadly. It usually starts with bacteria that cause a cold-like infection. It can cause stroke, hearing loss, and brain damage. It can also harm other organs. Pneumococcal infections and meningococcal infections are the most common causes of bacterial meningitis. Fungal meningitis is very rare, but is serious. Fungal meningitis usually only affects people with weakened immune systems.

Anyone can get meningitis, but it is more common in people with weak immune systems. Meningitis can get serious very quickly – it can kill in hours. You should get medical care right away if you have ⁷:

• A sudden high fever
• A severe headache
• A stiff neck
• Nausea or vomiting

Being able to recognise the symptoms of meningitis and septicaemia is vital because early recognition and treatment provide the best chance of a good recovery. Septicaemia is blood poisoning caused by the same germs that can cause meningitis.

Early treatment can help prevent serious problems, including death. Tests to diagnose meningitis include blood tests, imaging tests, and a spinal tap to test cerebrospinal fluid. Antibiotics can treat bacterial meningitis. Antiviral medicines may help some types of viral meningitis. Other medicines can help treat symptoms.

There are vaccines to prevent some of the bacterial infections that cause meningitis.

However, there are still some causes of meningitis and septicaemia which are not vaccine preventable and some vaccines are not routinely provided in some parts of the world.

Muscular dystrophy

Muscular dystrophy is a group of more than 30 inherited diseases. They all cause muscle weakness and muscle loss ⁹. In muscular dystrophy, abnormal genes (mutations) interfere with the production of proteins needed to form healthy muscle. Some forms of muscular dystrophy appear in infancy or childhood. Others may not appear until middle age or later. The different types can vary in whom they affect, which muscles they affect, and what the symptoms are. All forms of muscular dystrophy grow worse as the person’s muscles get weaker. Most people with muscular dystrophy eventually lose the ability to walk ⁹. Some may have trouble breathing or swallowing ¹⁰.

Duchenne muscular dystrophy

About half of people with muscular dystrophy have this variety ¹⁰. Although girls can be carriers and mildly affected, the disease typically affects boys.

About one-third of boys with Duchenne muscular dystrophy don’t have a family history of the disease, possibly because the gene involved may be subject to sudden abnormal change (spontaneous mutation).

Signs and symptoms typically appear between the ages of 2 and 3, and may include:

• Frequent falls
• Difficulty getting up from a lying or sitting position
• Trouble running and jumping
• Waddling gait
• Walking on the toes
• Large calf muscles
• Muscle pain and stiffness
• Learning disabilities

Becker muscular dystrophy

Signs and symptoms are similar to those of Duchenne muscular dystrophy, but typically are milder and progress more slowly. Symptoms generally begin in the teens but may not occur until the mid-20s or even later.

Other types of muscular dystrophy

Some types of muscular dystrophy are defined by a specific feature or by where in the body symptoms first begin. Examples include:

• Myotonic. Also known as Steinert’s disease, this form is characterized by an inability to relax muscles at will following contractions. Myotonic muscular dystrophy is the most common form of adult-onset muscular dystrophy. Facial and neck muscles are usually the first to be affected.
• Facioscapulohumeral (FSHD). Muscle weakness typically begins in the face and shoulders. The shoulder blades might stick out like wings when a person with FSHD raises his or her arms. Onset usually occurs in the teenage years but may begin in childhood or as late as age 40.
• Congenital. This type affects boys and girls and is apparent at birth or before age 2. Some forms progress slowly and cause only mild disability, while others progress rapidly and cause severe impairment.
• Limb-girdle. Hip and shoulder muscles are usually the first affected. People with this type of muscular dystrophy may have difficulty lifting the front part of the foot and so may trip frequently. Onset usually begins in childhood or the teenage years.

There is no cure for muscular dystrophy. Treatments can help with the symptoms and prevent complications. They include physical and speech therapy, orthopedic devices, surgery, and medications. Some people with muscular dystrophy have mild cases that worsen slowly. Others cases are disabling and severe.

Parkinson’s disease

Parkinson’s disease is a type of movement disorder. It happens when nerve cells in the brain don’t produce enough of a brain chemical called dopamine ¹¹. Sometimes it is genetic, but most cases do not seem to run in families. Exposure to chemicals in the environment might play a role.

Symptoms begin gradually, often on one side of the body. Later they affect both sides. They include ¹¹:

• Trembling of hands, arms, legs, jaw and face
• Stiffness of the arms, legs and trunk
• Slowness of movement
• Poor balance and coordination

As symptoms get worse, people with the disease may have trouble walking, talking, or doing simple tasks. They may also have problems such as depression, sleep problems, or trouble chewing, swallowing, or speaking.

There is no lab test for Parkinson’s disease, so it can be difficult to diagnose. Doctors use a medical history and a neurological examination to diagnose it.

Parkinson’s disease usually begins around age 60, but it can start earlier. It is more common in men than in women. There is no cure for Parkinson’s disease. A variety of medicines sometimes help symptoms dramatically. Surgery and deep brain stimulation can help severe cases. With deep brain stimulation, electrodes are surgically implanted in the brain. They send electrical pulses to stimulate the parts of the brain that control movement.

Spina bifida

Spina bifida is a neural tube defect – a type of birth defect of the brain, spine, or spinal cord. It happens if the spinal column of the fetus doesn’t close completely during the first month of pregnancy ¹². Normally, the neural tube forms early in the pregnancy and closes by the 28th day after conception. In babies with spina bifida, a portion of the neural tube fails to develop or close properly, causing defects in the spinal cord and in the bones of the spine. This can damage the nerves and spinal cord. Screening tests during pregnancy can check for spina bifida. Sometimes it is discovered only after the baby is born.

The symptoms of spina bifida vary from person to person. Most people with spina bifida are of normal intelligence. Some people need assistive devices such as braces, crutches, or wheelchairs. They may have learning difficulties, urinary and bowel problems, or hydrocephalus, a buildup of fluid in the brain.

The exact cause of spina bifida is unknown. It seems to run in families. Taking folic acid can reduce the risk of having a baby with spina bifida. It’s in most multivitamins. Women who could become pregnant should take it daily.

Spina bifida occurs in various forms of severity. When treatment for spina bifida is necessary, it’s done surgically, although such treatment doesn’t always completely resolve the problem.

Stroke

A stroke is a medical emergency. Strokes happen when blood flow to your brain stops ¹³. Within minutes, brain cells begin to die. There are two kinds of stroke. The more common kind, called ischemic stroke, is caused by a blood clot that blocks or plugs a blood vessel in the brain. The other kind, called hemorrhagic stroke, is caused by a blood vessel that breaks and bleeds into the brain. “Mini-strokes” or transient ischemic attacks (TIAs), occur when the blood supply to the brain is briefly interrupted.

Symptoms of stroke are ¹³, ¹⁴:

• Sudden numbness or weakness of the face, arm or leg (especially on one side of the body). You may develop sudden numbness, weakness or paralysis in your face, arm or leg, especially on one side of your body. Try to raise both your arms over your head at the same time. If one arm begins to fall, you may be having a stroke. Similarly, one side of your mouth may droop when you try to smile.
• Sudden confusion, trouble speaking or understanding speech. You may experience confusion. You may slur your words or have difficulty understanding speech.
• Sudden trouble seeing in one or both eyes. You may suddenly have blurred or blackened vision in one or both eyes, or you may see double.
• Sudden trouble walking, dizziness, loss of balance or coordination. You may stumble or experience sudden dizziness, loss of balance or loss of coordination.
• Sudden severe headache with no known cause. A sudden, severe headache, which may be accompanied by vomiting, dizziness or altered consciousness, may indicate you’re having a stroke.

Seek immediate medical attention if you notice any signs or symptoms of a stroke, even if they seem to fluctuate or disappear. Call your local emergency number right away. Don’t wait to see if symptoms go away. Every minute counts. The longer a stroke goes untreated, the greater the potential for brain damage and disability.

If you’re with someone you suspect is having a stroke, watch the person carefully while waiting for emergency assistance.

If you have any of these symptoms, you must get to a hospital quickly to begin treatment. Acute stroke therapies try to stop a stroke while it is happening by quickly dissolving the blood clot or by stopping the bleeding. Post-stroke rehabilitation helps individuals overcome disabilities that result from stroke damage. Drug therapy with blood thinners is the most common treatment for stroke.

1. Neurologic Diseases. Medline Plus. https://medlineplus.gov/neurologicdiseases.html[↩]
2. Alzheimer’s Disease. Medline Plus. https://medlineplus.gov/alzheimersdisease.html[↩]
3. National Center for Biotechnology Information (US). Genes and Disease [Internet]. Bethesda (MD): National Center for Biotechnology Information (US); 1998-. Alzheimer disease. Available from: https://www.ncbi.nlm.nih.gov/books/NBK22170/[↩][↩]
4. Epilepsy. Medline Plus. https://medlineplus.gov/epilepsy.html[↩]
5. National Center for Biotechnology Information (US). Genes and Disease [Internet]. Bethesda (MD): National Center for Biotechnology Information (US); 1998-. Epilepsy. Available from: https://www.ncbi.nlm.nih.gov/books/NBK22237/[↩][↩]
6. National Center for Biotechnology Information (US). Genes and Disease [Internet]. Bethesda (MD): National Center for Biotechnology Information (US); 1998-. Huntington disease. Available from: https://www.ncbi.nlm.nih.gov/books/NBK22226/[↩]
7. Meningitis. Medline Plus. https://medlineplus.gov/meningitis.html[↩][↩]
8. What are meningitis and septicaemia ? Meningitis Research Foundation. https://www.meningitis.org/meningitis/what-is-meningitis[↩]
9. Muscular Dystrophy. Medline Plus. https://medlineplus.gov/musculardystrophy.html[↩][↩]
10. Muscular dystrophy. Mayo Clinic. http://www.mayoclinic.org/diseases-conditions/muscular-dystrophy/basics/definition/CON-20021240?p=1[↩][↩]
11. Parkinson’s Disease. Medline Plus. https://medlineplus.gov/parkinsonsdisease.html[↩][↩]
12. Spina Bifida. Medline Plus. https://medlineplus.gov/spinabifida.html[↩]
13. Stroke. Medline Plus. https://medlineplus.gov/stroke.html[↩][↩]
14. Stroke. Mayo Clinic. http://www.mayoclinic.org/diseases-conditions/stroke/symptoms-causes/syc-20350113[↩]