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What Is Amblyopia?

Amblyopia is an early childhood condition in which one or (rarely) both eyes do not develop the normal capacity to see. It is one of the most common causes of irreversible visual impairment, affecting up to two percent of the population. The impairment can be mild to moderate, ranging from a relatively good 20/30 to a legally blind 20/200.

Because amblyopia affects the visual center of the brain which develops within the first five to six years of life, it must be treated in early childhood. After the age of five or six the condition becomes permanent.

Causes of Amblyopia

There are three basic causes of amblyopia:

Refractive Error: The eye may be very nearsighted, farsighted or have a lot of astigmatism. In these cases of refractive amblyopia, the images are so blurry that the brain never sees a normally focused image coming from the affected eye.

Eye Disease: Another disease, such as a cataract, obstructs light that normally enters the eye causing obstructive amblyopia. Or, in the case of a disease like optic nerve hypoplasia that damages the eye and vision, the damage is compounded by amblyopia.

Strabismus: The eyes may be crossed, otherwise known as strabismus. This situation may lead to strabismic amblyopia.

In This Section

Treatments and Procedures

Learn about treatment options available at Penn Medicine for amblyopia.

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