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What is amblyopia?

Amblyopia is reduced vision that happens when an eye does not develop normal sight during early childhood. It is also called a lazy eye.

How does it occur?

Normally, a newborn baby's vision is blurred. It improves as the baby gets older and uses her eyes. Both eyes work together (called binocular vision) and send pictures to the brain. The brain blends the two pictures into a single, clear picture. If pictures from each eye are different, or if one is blurry, the brain ignores the picture from one eye to avoid confusion. This may mean that normal vision does not develop in the eye that the brain ignores. After some time, this condition may become permanent.

The images from the eyes may be different due to:

  • Strabismus (also called crossed eyes): If your brain were to try to use the pictures coming from 2 eyes that are not aligned the same way, you would see double. To make sense of the confusing images, the brain ignores the picture coming from one eye.
  • Needing glasses: One eye may be more nearsighted, farsighted, or astigmatic than the other eye. These 3 vision problems keep the eye from focusing correctly. The brain uses the picture from the eye that sees better. The brain ignores the other eye which may stop developing.
  • Something blocking the vision: Cataracts and eyelid problems can keep the eye from opening all the way. This can prevent a young child's eyes from developing normally.

If this problem is found and treated when the child is young, both eyes may develop normal vision and work together. It is best to treat children before the age of 6. After the age of 8 years, the visual system is usually fully developed and treatment for amblyopia is less successful. However, even older children may benefit from treatment.

What are the symptoms?

Babies often do not show any symptoms of amblyopia. However, they may have trouble following an object with their eyes or may have crossed eyes. Toddlers may favor one eye. They may get fussy when the good eye is covered but not the other. Older children may complain of eye pain, watery eyes, or headaches. If you suspect that there is something wrong with your child's eyes at any age, talk to your healthcare provider. Most of the time, amblyopia is found during a vision exam at school or by a pediatrician.

How is it diagnosed?

A healthcare provider or preschool staff member may suggest that a child needs a complete eye exam. An eye care provider can diagnose amblyopia by watching how a baby or child follows objects with his eyes or by watching the baby's movements when one eye is covered.

How is it treated?

Treatment in children usually starts by putting a patch over the eye that has better vision. Patching forces the brain to use the weaker or "lazy" eye. Some providers prescribe eyedrops to blur the "good" eye instead of putting a patch on it. The eye care provider also treats the problem that led to the amblyopia. Glasses can help correct nearsightedness, farsightedness, or astigmatism. Crossed eyes may require eye muscle surgery, glasses, or both.

If amblyopia is found early and treated properly, a child can develop normal vision. If treatment does not take place early, glasses may provide good vision. However, the lazy eye may never see as well as the stronger eye and the eyes may not work together.

Most people can work and play well with one lazy eye. For example, Babe Ruth had amblyopia. However, airline pilots and interstate truck drivers, for example, are required by law to have good vision in both eyes.

Developed by RelayHealth.
Published by RelayHealth.
Last modified: 2009-12-10
Last reviewed: 2009-10-14
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
2010 RelayHealth and/or its affiliates. All Rights Reserved.
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