What is diplopia

Diplopia or double vision is when you look at 1 object but can see 2 images. Diplopia may affect 1 eye or both eyes.

Diplopia causes

Double vision has many possible causes, depending on whether one eye or both eyes are affected.

Try covering one eye at a time to see if your double vision goes away.

If you still have double vision in one eye with the other one covered, it’s probably only affecting that eye.

Double vision may be associated with:

• Trauma
• Black Eye / orbital fracture
• Cataract
• Migraine (ophthalmoplegic migraine)
• Microvascular cranial nerve palsy
• Strabismus
• Convergence insufficiency
• Accommodative insufficiency
• Myasthenia gravis
• Guillain-Barré syndrome
• Parkinson’s disease
• Tolosa-Hunt syndrome
• Thyroid eye disease
• Unilateral/bilateral 6th nerve (abducens) palsy
• Stroke
• Multiple Sclerosis (especially if bilateral)
• Tumor of brainstem or fourth ventricle
• Orbital cellulitis
• Cavernous hemangioma
• Ischemic disease: Hemorrhage, ischemic mononeuropathy
• Infectious process: post viral syndrome, chronic inflammation of petrous bone (recurrent ear infections), syphilis, basal meningitis
• Anatomical malformation: aneurysm, arteriovenous malformation (AVM), carotid-cavernous fistula, cavernous sinus thrombosis, pseudotumor cerebrii, Duane syndrome/Moebius syndrome, Chiari malformation
• Inflammatory disease: Sarcoidosis, granulomatosis with polyangiitis (formerly Wegener’s), Behcet’s disease
• Autoimmune condition: myasthenia gravis, thyroid disease, lupus
• Neoplastic disease: meningioma, neurogenic tumor, hemangioma, lymphoma/leukemia, schwannoma, pituitary adenoma, metastasis, CPA lesion, nasopharyngeal carcinoma, chordoma, chondrosarcoma, brain stem glioma in children
• Diabetes mellitus
• Head trauma
• Benign paroxysmal positional vertigo (BPPV)
• Meniere’s disease
• Toxicity (amitriptyline, ethanol, benzodiazepine)
• Chiari malformation
• Decompensated or “broken down” phoria
• Divergence insufficiency
• “Heavy eye” syndrome
• Skew deviation
• Decompensated phoria
• Divergence excess type intermittent exotropia
• Convergence paralysis associated with Parkinson’s disease or dorsal midbrain syndrome
• Medial rectus weakness secondary to myasthenia gravis or multiple sclerosis
• Dyslexia
• Uncorrected refractive error
• Syphilitic uveitis
• Sagging eye syndrome
• Internuclear ophthalmoplegia
• Carotid cavernous fistula
• ANCA-associated granulomatous vasculitis
• Orbital lymphoma
• Idiopathic orbital inflammatory syndrome
• Churg strauss syndrome
• Microscopic polyangiitis
• Relapsing polychondritis

Double vision affecting both eyes (binocular)

Binocular Double Vision is when double vision occurs in both eyes and it is due to both eyes being unable to work together produce a single image because of eye muscle problems (the medical term is strabismus). If you can cover either eye and the double vision subsides, it is likely binocular double vision.

Double vision affecting both eyes is usually a symptom of strabismus (a squint or “crossed eye”). Strabismus is a disorder in which both eyes do not line up in the same direction. Therefore, they do not look at the same object at the same time. This is where problems with the eye muscles or nerves cause the eyes to look in slightly different directions.

Strabismus are more common in children but they don’t always cause double vision. An untreated strabismus (a squint) in children under 7 causes a “lazy eye” (amblyopia) instead.

Squints in adults are sometimes a sign of a more serious condition.

Symptoms of strabismus may be present all the time or may come and go. Symptoms can include:

• Crossed eyes
• Double vision
• Eyes that do not aim in the same direction
• Uncoordinated eye movements (eyes do not move together)
• Loss of vision or depth perception

It is important to note that children may never be aware of double vision. This is because amblyopia can develop quickly.

Strabismus causes

Six different muscles surround each eye and work “as a team.” This allows both eyes to focus on the same object.

In someone with strabismus, these muscles do not work together. As a result, one eye looks at one object, while the other eye turns in a different direction and looks at another object.

When this occurs, two different images are sent to the brain — one from each eye. This confuses the brain. In children, the brain may learn to ignore (suppress) the image from the weaker eye.

If the strabismus is not treated, the eye that the brain ignores will never see well. This loss of vision is called amblyopia. Another name for amblyopia is “lazy eye.” Sometimes lazy eye is present first, and it causes strabismus.

In most children with strabismus, the cause is unknown. In more than one half of these cases, the problem is present at or shortly after birth. This is called congenital strabismus.

Most of the time, the problem has to do with muscle control, and not with muscle strength.

Other disorders associated with strabismus in children include:

• Apert syndrome
• Cerebral palsy
• Congenital rubella
• Hemangioma near the eye during infancy
• Incontinentia pigmenti syndrome
• Noonan syndrome
• Prader-Willi syndrome
• Retinopathy of prematurity
• Retinoblastoma
• Traumatic brain injury
• Trisomy 18 (Edwards’ syndrome)

Strabismus that develops in adults can be caused by:

• Botulism
• Diabetes (causes a condition known as acquired paralytic strabismus)
• Graves disease
• Guillain-Barré syndrome
• Injury to the eye
• Shellfish poisoning
• Stroke
• Traumatic brain injury
• Vision loss from any eye disease or injury

A family history of strabismus is a risk factor. Farsightedness may be a contributing factor, often in children. Any other disease that causes vision loss may also cause strabismus.

Double vision affecting one eye (monocular)

Monocular double vision is when double vision occurs in only one eye. The distorted vision is an effect known as “ghosting” and is when doubled images appear very close together. Rather than clearly seeing a double image, you may instead see the second image slightly displaced from the main image of whatever it is you are looking at. If you were to cover the unaffected eye, you will still experience double vision.

Double vision affecting one eye is less common. It’s usually caused by eye problems such as:

• Dry eye syndrome – where the eyes don’t produce enough tears
• Astigmatism – a common condition where part of the eye isn’t a perfect shape
• Cataracts – cloudy patches over the front of the eyes
• Keratoconus – where the clear outer layer of the eye (cornea) gets thinner and changes shape

Double vision treatment

Double vision treatment depends on the underlying conditions. Usually, the treatment will be symptomatic and aimed at reducing the bothersome diplopia the patient experiences. In most cases, this is achieved with prismatic correction in glasses. In cases where the deviation is too large to be corrected with prisms and has been stable for a period of at least six months, strabismus surgery can be considered. Finally, conditions such as giant cell arteritis, myasthenia gravis, and thyroid eye disease have specific treatments, including corticosteroids in all cases, anticholinesterase medications and immunosuppressive agents in myasthenia gravis and orbital decompression, strabismus surgery, and lid surgery (in this specific order) for thyroid eye disease.