What is strabismus?

Strabismus is a condition in which the 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 the eyes may turn in, out, up or down.


Coordination of the eyes and their ability to work together as a team develops in the first six months to four years of life. Failure of your eye muscles to work together properly can lead to strabismus. Strabismus can 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 21 months. It is estimated that five per cent of all children have some type or degree of strabismus. It can also sometimes begin in adulthood. Sudden onset may occur as a result of a stroke, tumor, vascular disease.

Will a child outgrow it?

No. In fact, the condition may simply become worse without treatment, potentially leading to an amblyopic (lazy) eye.


Double vision can occur when both eyes are not focusing on the same object. In an attempt to avoid double vision, the child’s 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).


Parents may be the first to notice a slight wandering of one or both of a child’s eyes. A comprehensive eye examination by an optometrist is recommended by six months of age or sooner if an eye appears to be misaligned.


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


“Strabismus” Ontario Association of Optometrists, Retrieved 13 June 2019. <https://www.optom.on.ca/OAO/Patients/Library/Strabismus.aspx>