Definition: Strabismus is a visual defect in which the eyes are misaligned and point in different directions.

Causes: The brain controls the eye muscles. Most children with strabismus have no neurologic deficits. Strabismus is especially common among children with disorders that affect the brain such as cerebral palsy, Down's Syndrome, hydrocephalus, and brain tumors. Cataracts or an eye injury affecting the vision can also cause strabismus. In infants, pseudostrabismus (the illusionary appearance of crossed eyes) is not uncommon.

An adult with strabismus without a childhood history of misaligned eyes needs to be evaluated for medical or neurological causes such as diabetes, thyroid disease, myasthenia gravis, brain tumors or strokes.

The most common types are Estropia, where the eye turns inward and Exotropia, where the eye turns outward.

Strabismus in Children: In a young child, the brain learns to ignore the image from the misaligned eye and processes only the image from the stronger eye. this causes a loss of depth perception. It can also cause loss of vision in the misaligned eye. If detected early, however, the condition is usually successfully treated.

Strabismus in Adults: When the condition develops late in childhood or in an adult, the brain is no longer able to suppress the image from the weaker eye and the result is double vision.

Treatment: Corrective lenses, surgery, and, occasionally, eye exercises are options in treatment. An ophthalmologic evaluation is required to determine the extent and recommended treatment.