Exophoria is the term for one eye drifting uncontrollably outwards. Exophoria may cause blurred or double vision, eye fatigue, and difficulty focusing on objects.

Exophoria is a problem with eye coordination and may occur due to issues with the muscles and nerves that control eye movements.

This article discusses the symptoms and causes of exophoria.

It also examines similar conditions, diagnosis, treatment, and outlook.

A person covering one eye during an eye test for exophoria.Share on Pinterest
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Exophoria is an eye coordination problem that causes one eye to drift outwards. It typically presents during childhood.

“Convergence insufficiency” is an eye condition that affects how the eyes work together and makes it difficult to view objects up close. Convergence insufficiency occurs if the eye cannot turn inward enough to view an object.

If the eye drifts outwards while looking at objects in the distance, doctors may refer to it as divergence excess.

Learn more about convergence insufficiency.

Symptoms of exophoria may include:

  • sore or tired eyes
  • rubbing the eyes
  • double vision
  • blurred vision
  • difficulty concentrating
  • difficulty reading, such as losing the place or the sensation of words floating around
  • headaches
  • squinting
  • closing one eye to see something

Depending on the type of exophoria, people may find it difficult to focus on objects close-up or in the distance.

The following eye conditions share some symptoms with exophoria:


Exotropia is a type of strabismus, which is the term for eye misalignment. With exotropia, one or both of the eyes turn outwards. Exotropia may happen occasionally or constantly.

People may develop exotropia at birth or acquire the condition. Wearing glasses or using a patch may help resolve symptoms of exotropia. In some cases, surgery may be necessary to realign the eyes.

In some cases, vision therapy can be helpful in treating exotropia.


Esotropia is the opposite of exotropia. Esotropia is the term for crossed eyes or when the eyes turn inward.

Learn more about esotropia.


Amblyopia, or lazy eye, is a condition where poor vision affects one eye or sometimes both.

Amblyopia occurs if there is a problem with communication between the brain and the eye, causing the brain to rely on one eye more than the other for sight. Over time, vision in the weaker eye worsens.

Amblyopia begins in childhood, and treatment can help to prevent vision loss. Treatment may include using a patch or medicated eye drops to temporarily affect vision in the stronger eye and help improve vision in the weaker eye.

Learn more about amblyopia.

Issues with eye coordination may occur due to poor eye muscle control. If eye muscle control does not develop properly, it can lead to poor coordination of the eyes. In some cases, eye coordination problems may occur due to injury or disease, although this is rare.

Muscles and nerves help to control eye movements. If these muscles and nerves do not communicate properly, it can lead to problems controlling eye movements. This may result in the eye drifting outward and being unable to turn inward enough.

Head injuries may increase the risk of eye conditions that cause one eye to turn outward. Convergence insufficiency may be more common following a concussion or brain injury.

Children with a family history of eye coordination issues are more likely to experience exophoria.

Problems with eye coordination can be difficult to notice, so eye doctors, such as ophthalmologists and optometrists, use a thorough eye examination to diagnose exophoria. A comprehensive eye exam may include the following:

  • Symptoms and medical history: An eye doctor will assess a person’s symptoms and vision problems.
  • Visual acuity test: This measures how well each eye is working. A doctor may ask the person to read letters on a chart at varying distances.
  • Preliminary tests: These measure different eye functions and features of eye health, such as depth perception, color vision, and peripheral vision.
  • Keratometry: This measures the curve of the cornea.
  • Refraction: A doctor will place a selection of lenses in front of the eyes and test how they focus light. Refraction helps a doctor to see how well the eye focuses.
  • Eye focusing tests: A doctor will use different tests to assess how the eyes move and focus. These show how well the eyes are working together to see clearly.
  • Eye health tests: A doctor may use eye drops to dilate the pupil to examine structures within the eye better.
  • Additional tests: Depending on the results of the previous tests, a doctor may carry out further tests to clarify any findings.

Read about ophthalmologists and optometrists here.

Treatment for exophoria may include wearing glasses or vision therapy.

Eyeglasses may help to pull the eyes inward. Glasses known as base-out prism glasses can help to make the eyes focus inward rather than outward, but they can tire the eyes over long periods.

Vision therapy may include convergence exercises. An eye specialist can provide people with suitable exercises to do at home. Eye exercises may involve focusing on objects at varying distances.

In rare cases, people require surgery for an eye coordination problem. Surgery may help to strengthen eye muscles if other treatments are ineffective.

Treatment can help to correct exophoria. With treatment, people may notice an improvement in eye coordination right away, or it may take 12 weeks or longer to notice improvements in vision.

People may also find that symptoms reoccur with a lack of sleep, illness, or activities that trigger their exophoria, such as focusing on close-up activities like reading or using a computer.

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Exophoria occurs when one eye involuntarily turns outward. It is a type of eye coordination problem and may occur due to an issue with the muscles or nerves that control eye movements.

Treatment may help to resolve exophoria. This can include wearing glasses, vision therapy, and, in some cases, surgery.