Strabismus (crossed eyes)

A crossed eye or out-turned eye is referred to clinically as strabismus.

Last Updated: March 18, 2023

What is a crossed eye or strabismus?

A crossed eye or out-turned eye is referred to clinically as strabismus. It is a muscle condition in which your eyes are not properly aligned with each other, resulting in double vision or the suppression of the image from the affected eye. For a variety of reasons, one or both of your eyes may turn in, out, up or down.

What causes strabismus?

Coordination of your eyes and their ability to work together as a team develops in your first six to eight years. Failure of your eyes, or more precisely, your eye muscles, to work together properly can lead to strabismus. It has a tendency to be hereditary, but may also be acquired secondary to an eye injury or disease.

Who is affected by strabismus?

Children under age six are most affected by strabismus, but it usually first appears between birth and age 21 months. It is estimated that five per cent of all children have some type or degree of strabismus. Although rare, strabismus can sometimes begin in adulthood; this is usually the result of a stroke, tumor or other vascular disease.

Will a child outgrow strabismus?

A child will not outgrow strabismus without treatment. In fact, the condition may simply become worse without treatment.

What are the effects of strabismus?

Children with strabismus may initially have double vision. This occurs because both eyes are not focusing on the same object. In an attempt to avoid double vision, the brain will eventually disregard the image from one eye. This is referred to as suppression. In time, the ignored eye will become unable to function normally and will become largely unused. This may result in the development of lazy eye (amblyopia).

How is strabismus diagnosed?

Parents may be the first to notice a slight wandering of one or both of a child’s eyes. A comprehensive eye examination by a doctor of optometry is recommended at six months of age and then yearly after age three. The examination can determine if strabismus is present.

How is strabismus treated?

Treatment for strabismus can include eyeglasses (single vision or bifocal), prisms, vision therapy, and in some cases, surgery. Strabismus can be corrected with excellent results if detected and treated early.