Amblyopia Fact Book

The brain and the eye work together to produce vision. Light enters the eye and is changed into nerve signals that travel along the optic nerve to the brain. Amblyopia is the medical term used when the vision in one of the eyes is reduced because the eye and the brain are not working together properly. The eye itself looks normal, but it is not being used normally because the brain is favoring the other eye. This condition is also sometimes called lazy eye.

How common is amblyopia?

Amblyopia is the most common cause of decreased vision in children. The condition affects approximately 2 or 3 out of every 100 children. It is estimated that as many as three percent of children in the U.S. have some degree of vision impairment due to amblyopia. Unless it is successfully treated in early childhood, amblyopia usually persists into adulthood, and is the most common cause of monocular (one eye) visual impairment among children and young and middle-aged adults.

What causes amblyopia?

Amblyopia may be caused by any condition that affects normal visual development or use of the eyes. Amblyopia can be caused by strabismus, an imbalance in the positioning of the two eyes. Strabismus can cause the eyes to cross in (esotropia) or turn out (exotropia). Sometimes amblyopia is caused when one eye is more nearsighted, farsighted, or astigmatic than the other eye. Occasionally, amblyopia is caused by other eye conditions such as cataract.

Amblyopia treatment is most effective when done early in the childŐs life, usually before age 7. Treating amblyopia involves making the child use the eye with the reduced vision (weaker eye). Currently, there are two ways used to do this:

Atropine
A drop of a drug called atropine is placed in the stronger eye once a day to temporarily blur the vision so that the child will prefer to use the eye with amblyopia. Treatment with atropine also stimulates vision in the weaker eye and helps the part of the brain that manages vision develop more completely.

Patching
An opaque, adhesive patch is worn over the stronger eye for weeks to months. This therapy forces the child to use the eye with amblyopia. Patching stimulates vision in the weaker eye and helps the part of the brain that manages vision develop more completely. To be effective, patching must usually be done for a minimum of six hours each day.

Can amblyopia be treated in adults?

During the first six to nine years of life, the visual system develops very rapidly. Complicated connections between the eye and the brain are created. We do not yet have the technology to create these eye-to-brain connections in older children and adults.

Scientists are exploring whether treatment for amblyopia in older children and adults can improve vision.

Keeping in tune with your disease or condition not only makes treatment less intimidating but also increases its chance of success, and has been shown to lower a patients risk of complications. As well, as an informed patient, you are better able to discuss your condition and treatment options with your physician.

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Resources

The following organizations may be able to provide additional information on amblyopia:

National Eye Institute
2020 Vision Place
Bethesda, MD 20892-3655
(301) 496-5248
http://www.nei.nih.gov/
Conducts and supports vision research. Part of the National Institutes of Health.

American Academy of Ophthalmology
P.O. Box 7424
San Francisco, CA 94120-7424
(415) 561-8500
http://www.aao.org
Represents board-certified ophthalmologists in the United States. Provides information for the public on amblyopia.

American Association for Pediatric Ophthalmology and Strabismus
P.O. Box 193832
San Francisco, CA 94119-3832
(415) 561-8505
http://www.aapos.org
Represents ophthalmologists that specialize in providing eye care for children.

American Optometric Association
243 N. Lindbergh Boulevard
St. Louis, MO 63141
(314) 991-4100
http://www.aoa.org
Represents optometrists in the United States. Provides information for the public on amblyopia.

For additional information, you may wish to contact a local library.