Amblyopia (Lazy Eye), is the loss or lack of development of central vision in one eye that is unrelated to any eye health problem and is not correctable with lenses. It can result from a failure to use both eyes together.  Amblyopia (Lazy Eye) is often associated with crossed-eyes or a large difference in the degree of nearsightedness or farsightedness between the two eyes. It usually develops before the age of 6, and it does not affect side vision.

The second subtype, refractive amblyopia, occurs when abnormal vision stems from uncorrected refractive error, most commonly hyperopia (farsightedness) or astigmatism (irregular curvature of the cornea), at a young age. Visual images in both eyes are degraded, resulting in abnormal visual processing.

Symptoms may include noticeably favoring one eye or a tendency to bump into objects on one side.  It often begins during infancy and early childhood. In most cases, only one eye is affected. Symptoms are not always obvious. Treatment for lazy eye may include a combination of prescription lenses, prisms, vision therapy and eye patching. Vision therapy teaches the two eyes how to work together, which helps prevent lazy eye from reoccurring.