Eye Health: Amblyopia and Your Child's Eyes

Amblyopia is a condition that occurs in children when one eye has poorer vision than the other. If amblyopia is left untreated, a child's vision will not develop correctly. The child's brain, as it matures, will start "ignoring" the image coming from the bad eye. This causes vision in the affected eye to become poor. Because amblyopia can result in permanent vision loss in one eye, it is important to have a child with amblyopia regularly tested by an eye doctor.

What Causes Amblyopia?

Amblyopia usually starts when one eye has much better focus than the other eye. For example, one eye might be very nearsighted or have a lot of astigmatism, while the other does not. When the child's brain is confronted with both a blurry image and a clear image, it will begin to ignore the blurry image. If this goes on for months or years, the vision in the eye that sees the blurry image will deteriorate.

Another cause of amblyopia is called strabismus. Strabismus is an ocular misalignment, meaning that one eye turns inward or outward. This prevents the eyes from focusing together on an image and can cause double vision. In order to combat this, the child's brain generally chooses to ignore the image from the deviated eye, causing the vision in that eye to deteriorate. Because one of the eyes is misaligned, some people refer to this as a "lazy eye."

Other children cannot see well in one eye because something blocks light from getting through. This could be due, among other causes, to a cataract or a small amount of blood or other material in the back of the eye.

How Is Amblyopia Diagnosed?

Your child's doctor or the vision program at school will check three aspects of your child's eye health:

1. That your child's eyes let light all the way through.
2. That both eyes see equally well.
3. That the eyes are moving normally.

If there's a problem in any of those three areas, the doctor or school nurse may recommend a visit to an eye specialist.

All children should be screened before they are school age. Also, if parents notice any crossing of the eyes or are concerned about their child's vision, they should be evaluated promptly. Family history of amblyopia is a risk factor for amblyopia. Parents cannot tell just by looking at their child if they have amblyopia. Early diagnosis and treatment are the keys to the best visual outcome.

How Is Amblyopia Treated?

The most common treatment for amblyopia is to force the brain to start using the "bad" eye by putting a patch over the "good" eye. At first, the child will have a hard time seeing with just the weaker eye. However, it is very important that your child wear the patch diligently because this will eventually improve vision. It can take weeks or months for an eye patch to improve vision.