Amblyopia (Lazy Eye)

What is amblyopia?

Amblyopia occurs when one eye is used more than the other. It is also called “lazy eye.” It happens when the weaker eye does not work well with the brain. The eye looks normal, but the brain ends up favoring the other eye, and it becomes the stronger eye.

Amblyopia is the most common vision problem in children, affecting as many as 3 percent of all kids. It’s very important to diagnose and treat amblyopia as early as possible to prevent it from lasting into adulthood.

What causes amblyopia?

Any condition that keeps an eye from focusing clearly can cause amblyopia. Examples include:

• “Crossed eyes” and other problems with eye alignment (strabismus). The eyes can point out (exotropia) or cross inward (esotropia).
• Clouding of the lens of the eye (cataract).
• Eye focus problems. Being farsighted (having eyes that focus better at a distance than closer) or nearsighted (having eyes that focus better on near objects than far ones) or having astigmatism (irregularly shaped eyes) can cause amblyopia.

How is amblyopia diagnosed?

The best way to diagnose amblyopia is an examination by an eye care professional. An ophthalmologist (eye physician) can determine if a child’s vision differs between both eyes. The doctor can see how an infant or young child tracks a moving object when one eye is covered. A full medical eye exam is beneficial because it enables the doctor to look for any eye problems that may be impairing vision.

How is amblyopia treated?

Amblyopia treatments center on “retraining” the weaker eye to work more effectively than the brain, essentially strengthening it so it works as efficiently as the dominant eye. The vision system develops quickly during the first decade of life, with vital connections forged between the eyes and the brain. So treating amblyopia early, during this time, is very important. The jury is still out on whether amblyopia in adults can be treated.

If your child has amblyopia, your eye doctor may recommend one of these strategies:

• Wearing a patch over the stronger eye for several hours a day, forcing your child to rely on the weaker eye. This method stimulates vision in the lazy eye and encourages the brain to cooperate better with that eye. Studies have shown that patching is a very effective way to treat amblyopia, but it must be done regularly. It can take weeks or months to work.
• Medication to blur vision. A drug called atropine, given as eyedrops, can cause blurriness in the stronger eye, again forcing your child to use the weaker eye. These drops offer an alternative to strengthening the lazy eye in children who may be resistant to wearing an eye patch. Wearing glasses with a lens that blurs vision in the stronger eye can achieve similar results.

Source: The National Eye Institute (NEI)