Lazy eye (amblyopia) is a reduction in visual acuity that results from abnormal visual development during infancy and early childhood. Lazy eye usually affects just one eye, but it may affect both eyes. With lazy eye, there is no apparent damage or abnormality to the eye. Lazy eye is the leading cause of decreased vision among children. Left untreated, the loss of vision may range from mild to severe.
Lazy eye develops when nerve pathways between the brain and the eye aren't properly stimulated. This can lead to a condition in which the brain favors one eye, usually due to poor vision in the other eye. The weaker eye tends to wander. Eventually, the brain may ignore the signals received from the weaker — or lazy — eye.
Conservative treatments such as corrective eye wear or eye patches can often correct lazy eye. Sometimes, lazy eye requires surgical treatment.