Amblyopia (Lazy Eye)

Amblyopia, also known as lazy eye, is a condition characterized by diminished vision in one eye. Amblyopia is the most common cause of visual impairment restricted to one eye in children and young to middle-aged adults. It's estimated that about 5% of children in the United States have amblyopia.

Amblyopia is not correctable by eyeglasses or contact lenses alone and is not usually triggered by an eye disease. All babies are born with poor eyesight that normally improves as they grow. In amblyopia, one eye becomes stronger. If the weaker eye is untreated, eyesight will progressively worsen.


The two most common types of amblyopia are strabismic and anisometropic. In strabismic amblyopia, strabismus is present and the eyes are not aligned properly resulting in one eye being used less than the other. The less-used eye is not adequately stimulated and the visual brain cells do not develop normally. With anisometropic amblyopia, the eyes have different refractive powers. For example, one eye may be nearsighted and the other farsighted. It may be difficult for the brain to balance the difference and it favors the stronger eye. Anything that interferes with equal development of vision in both eyes between birth and about six years can result in amblyopia.

Signs and Symptoms

Amblyopia may not produce symptoms that are obvious to a parent or the affected child. Amblyopia caused by an undetected refractive error may go unnoticed for years, due to the fact that one of the eyes is functioning normally. As a result, many children remain unaware of vision problems, especially before they begin school. The condition is often diagnosed during the first eye examination at a later age, when improvement in vision to its fullest potential may no longer be possible.

Sometimes, though, a child may squint or close one eye, which indicates a visual problem. A child old enough to verbalize may complain of headaches or eyestrain. If you notice your child having these problems be sure to see your eye doctor for a complete examination.


Treatment that includes patching the good eye may help the amblyopic eye to improve. In addition, to help improve vision function, vision therapy techniques may be used. Eyeglasses or contact lenses may be prescribed to correct any refractive errors. A better outcome is achieved the earlier that amblyopia is diagnosed and treatment is initiated.

Amblyopia is a challenge because it can limit the work and leisure activities one can do. Activities requiring good depth perception may be difficult or impossible to perform. In addition, should your good eye become injured or develop problems, you may have difficulty maintaining normal activities.