Cataract is the most common cause of double vision. Other causes being diabetes, myasthenia gravis, thyroid eye disease, multiple sclerosis, raised pressure in the brain, brain tumors, migraine, aneurysms and strokes.
Causes of diplopia can also be divided into those causing uniocular diplopia and those causing binocular diplopia.
Binocular Diplopia:Binocular diplopia occurs due to misalignment of the eyes. The movements of the eyes are controlled by eye muscles. The movement of the eye is affected by diseased muscle or problem with the nerve supplying the muscle.
- Myasthenia Gravis- It is an autoimmune disease in which the there is blockage of stimulation of the muscle by the nerve due to a problem at the nerve end. The commonest symptom of this disease is diplopia. Patients also frequently have droopy lids.
- Thyroid eye disease: It weakens the eye muscle and commonly causes diplopia.
Conditions like multiple sclerosis, uncontrolled diabetes and Guillian Barre syndrome can affect the nerves supplying the eye muscles and cause a muscle paralysis leading to squint and diplopia.
Some causes for double vision originate in the brain. They include:
- Increased pressure inside the brain from trauma, bleeding, or infection
- Brain tumors
- Migraine headaches
Diplopia due to these causes requires immediate medical assistance.
Cataract is the commonest cause of uniocular diplopia.
Corneal disorders can also rarely cause uniocular diplopia.. The damaged surface of the eye distorts incoming light, causing double vision. Corneal disorders are due to infections or rare complication of LASIK surgery.