What causes amblyopia?

Diana Meeks
Diana Meeks on behalf of Sigma Nursing
Family Practitioner

There are a number of causes associated with amblyopia, or lazy eye. In fact, almost any vision development condition can cause it. Common causes include strabismus, or imbalanced eye position. You'll notice strabismus if the eyes cross or if both eyes turn outward. Someone may also develop amblyopia if one eye is more farsighted or nearsighted than its counterpart. More serious conditions, such as cataracts or even tumors, have also been known to result in amblyopia.

Amblyopia is caused by any condition that affects normal use of the eyes and visual development. In many cases, the conditions associated with amblyopia may be inherited. Amblyopia has three major causes:
Strabismus (misaligned eyes)
Amblyopia occurs most commonly with misaligned or crossed eyes. The crossed eye “turns off” to avoid double vision, and the child uses only the better eye. The misaligned eye then fails to develop good vision.
Unequal Focus and Refractive Errors
Refractive errors are eye conditions that are corrected by wearing eyeglasses. Amblyopia occurs when one eye is out of focus because it is more nearsighted, farsighted or astigmatic than the other.
The unfocused (blurred) eye “turns off” and becomes amblyopic. The eyes can look normal, but one eye has poor vision. This is the most difficult type of amblyopia to detect since the child appears to have normal vision when both eyes are open.
Amblyopia can also occur in both eyes if both eyes have very blurred vision. This can happen when there is a high amount of nearsighted-ness, farsightedness or astigmatism.
Cloudiness in the Normally Clear Eye Tissues
An eye disease such as a cataract (a clouding of the eye’s naturally clear lens) may lead to amblyopia. Any factor that prevents a clear image from being focused inside the eye can lead to the development of amblyopia in a child. This is often the most severe form of amblyopia.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.