Amblyopia

Amblyopia, often called "lazy eye," is poor vision or reduced vision in an eye that didn't develop normally in childhood. According to the American Academy of Ophthalmology (AAO), the condition is one of the most common causes of vision problems in children. If left untreated, amblyopia can mean a lifetime of poor vision in one eye that cannot be improved. (Read about "The Eye")

Causes

To understand amblyopia, one must understand the basics of how babies develop sight. Like walking and talking, seeing is a learned behavior. A newborn can see, but has to learn to use its eyes to focus and then coordinate both eyes into a stereoscopic system. But if an image is not clear in one eye, or if the image isn't the same in both eyes, the vision pathways from the eyes to the brain won't develop correctly. (Read about "The Brain")

AAO lists three major causes of amblyopia:

• Strabismus (misaligned or "crossed eyes") - This is the most common form. One eye may look straight ahead, while the other turns inward or outward, up or down. The brain "turns off" the image from the weak eye to avoid double vision and the child uses only the better eye.
• Unequal focus (Refractive error) - This occurs when one eye is out of focus because it is more nearsighted, farsighted or astigmatic than the other. Again, the brain deletes the image from the weak eye, and only the better eye is used. (Read about "Refractive Errors")
• Cloudiness in eye tissues (which are normally clear) - This is often the most severe form of amblyopia and is caused by anything which prevents a clear image from being focused inside the eye. Childhood cataracts (cloudiness of the eye's lens) can be one cause. (Read about "Cataracts")

Some conditions, such as Turner syndrome (Read about "Turner Syndrome"), also increase the risk of amblyopia.

Diagnosing the problem

Sometimes it is not easy to recognize amblyopia. Unless the child has a misaligned eye, or other obvious abnormality, there is often no way for parents to tell that something is wrong. The American Optometric Association (AOA) recommends that children have a comprehensive optometric exam at the age of six months, and again at age three or four. (Read about "Eye Exams") AOA says "lazy eye" will not go away on its own. By the time a child is 8 to 10, the brain's vision system is complete and can't be changed. If not treated, the "lazy" eye may become functionally blind.

Treatment

According to the American Academy of Family Physicians (AAFP) the earlier treatment begins, the faster and better the result. AAFP says with early diagnosis and treatment, the sight in the lazy eye can be restored. To correct amblyopia, the weaker eye must be made to work. AAO lists several treatments:

• The most common is patching or covering the good eye for a period of time ranging from a few weeks to as long as a year. By working the weak eye, vision can be restored.
• Surgery may be necessary to correct causes of amblyopia such as strabismus or cataracts.
• Glasses may be prescribed to correct focusing problems.
• Eye drops or ointments may be used to blur the vision of the strong eye.

Some recent studies have suggested that eye drops can be as effective as patching. Patching, however, remains the main treatment.

Tips on patching

Patching is hard work. Many children object to wearing a patch that can be uncomfortable. Prevent Blindness America has a few tips for parents:

• Be patient. Patching gets easier. Most children will learn to tolerate the patch particularly if vision starts to improve in the bad eye.
• Be creative. Decorating the patch can distract your child.
• Treat skin irritation. Some children will experience a rash where the patch is attached to the face. Soothe with skin cream or medicated ointment. (Read about "Skin Rash")
• If your child is old enough, explain why the patch is necessary and the consequences of not following the prescribed treatment plan.
• Talk to your child's teachers. They can often explain the problem to other students. This can help your child feel more comfortable in the classroom.
• Don't give up too soon.

If the patching is proving impossible, it may be reasonable to take some time off before trying again. As long as the child is still young, there should be time to reverse the amblyopia. Talk to your doctor!

Related Information:

    Eyes and Sun

    Glossary of Vision Terms