Double Vision (Diplopia)

Double vision — diplopia — is a vision disorder in which a person perceives two images of a single object. It can happen with one eye (monocular diplopia) or with both eyes open (binocular diplopia). Sorting out which one you have is the first job of an evaluation, because the two have different causes and different treatments.

Sudden, new, or persistent double vision should always be evaluated promptly to rule out medical causes. Once anything urgent has been addressed, the next question is whether the doubling is coming from inside one eye or from the way the two eyes aim together.

Monocular Diplopia: Double Vision in One Eye

• The doubling is still there when the other eye is closed.
• It is usually caused by a structural difference in the eye itself — astigmatism, keratoconus, a pterygium, or a cataract.
• Monocular diplopia is addressed by treating that underlying eye condition, not by retraining eye teaming.

Binocular Diplopia: Double Vision With Both Eyes Open

• The doubling happens with both eyes open and resolves when one eye is closed.
• It is often due to a misalignment of the eyes: the eyes do not aim at the same point, so the brain receives two images instead of fusing them into one.
• Causes include strabismus, nerve damage such as a cranial nerve palsy, muscle weakness, or problems with the brain such as a stroke or tumor.
• Treatment may involve addressing the underlying cause, prism glasses to realign the two images, vision therapy to coordinate the eyes and the brain, or surgery in some cases.

Causes of Double Vision

• Neurological. Multiple sclerosis, strokes, or brain tumors can cause double vision by affecting the nerves that control the eye muscles.
• Muscular. Conditions like myasthenia gravis affect the muscles controlling eye movement, leading to double vision.
• Nerve. Guillain-Barré syndrome, diabetes, or a cranial nerve palsy can affect the nerves that control the eye muscles. A third, fourth, or sixth nerve palsy may also show up as a drooping eyelid, a habitual head tilt, or an eye that will not turn outward.
• Eye conditions. Cataracts, refractive-surgery complications, or irregularities in the cornea or lens can lead to double vision in one eye.
• Trauma. Injury to the eye, the orbit, or the brain can lead to double vision — one reason it is a common complaint after a concussion and a focus of vision rehabilitation.
• Graves’ disease. This autoimmune disorder can cause swelling of the muscles and tissues around the eyes, leading to double vision.

Diagnosis and Treatment

A binocular vision evaluation is what identifies the cause. It looks at how each eye sees on its own, how the two eyes align and team at distance and near, and whether the doubling persists when one eye is covered — the finding that separates monocular from binocular diplopia.

Treatment follows the cause. It may mean managing an underlying medical or eye condition, prism glasses to bring the two images together, vision therapy to build the eye-teaming and focusing control that holds a single image, or surgery in some cases. When the double vision follows a stroke, brain injury, or neurological condition, that work is part of vision rehabilitation, coordinated with your medical team.

Not sure whether what you are noticing counts? Our symptom checklist is a quick way to organize what you are seeing, and Problems We Solve connects everyday complaints to the visual skills behind them. For plain-language reading, see Double Vision in Children, Prism Glasses vs. Vision Therapy, and one patient’s story of overcoming double vision and headaches.

Care starts with a comprehensive developmental and binocular vision evaluation that pinpoints exactly what's happening. From there, Dr. Murray builds an individualized plan — which may include lenses or prism, in-office vision therapy, and coordination with your other providers — at our Boynton Beach and Boca Raton offices.