Amblyopia, commonly called “lazy eye,” is a condition in which vision does not develop normally in one eye, or sometimes both eyes, during childhood. The brain and eye are not working together as they should, so the brain begins to rely more on the stronger eye. As a result, the affected eye has reduced vision that cannot be fully corrected with glasses alone.
It is important to know that amblyopia is not the same as an eye that wanders or crosses. Many people use the term “lazy eye” to describe an eye that turns inward, outward, or in another direction. That condition is called strabismus. Strabismus can cause amblyopia, but a child can have amblyopia without having an eye that visibly turns.
What Causes Amblyopia?
Amblyopia develops when the brain does not receive equally clear images from both eyes while vision is developing. Several conditions can lead to this problem.
One common cause is a difference in the prescription between the two eyes. If one eye is much more nearsighted, farsighted, or astigmatic than the other, the brain may favor the eye with clearer vision.
Strabismus can also cause amblyopia. When the eyes point in different directions, the brain may ignore the image from one eye to avoid seeing double.
Amblyopia can also occur when something blocks or severely reduces vision in one eye. A cataract present during childhood, for example, can interfere with normal visual development.
Why Early Treatment Matters
Amblyopia usually begins in infancy or early childhood, when the visual system is still developing. Without treatment, reduced vision can become long-lasting. The good news is that finding and treating amblyopia early can improve a child’s vision.
Treatment depends on the cause and severity of the condition. Glasses may be enough for some children, especially when the problem is related to an unequal prescription. Other children may need to wear an eye patch over the stronger eye for part of the day. This encourages the brain to use the weaker eye. In some cases, special eye drops are used to temporarily blur vision in the stronger eye.
How Is Amblyopia Diagnosed?
Amblyopia is diagnosed through a comprehensive eye examination. Your eye doctor will check each eye’s vision, eye alignment, focusing ability, and overall eye health. Children may not realize that they are seeing poorly because they have adapted to using their stronger eye.
That is why routine children’s eye exams and vision screenings are important, even when a child does not complain about vision problems.
If you notice an eye that turns, difficulty seeing, unusual head tilting, or other changes in your child’s vision, schedule an eye examination. Early diagnosis and treatment can help give your child’s developing visual system the best opportunity to achieve clear vision.