Q: What is it?
A: Amblyopia is commonly known as "lazy eye". It occurs when the eyes, for some reason, have not learned to work together. There are two types. One is caused by toxic substances such as alcohol or tobacco. The second type is caused by lack of use. Amblyopia can effect almost everyone, but it is most prevalent among children and infants. The majority of cases are caused by lack of use and are found in children. Children do not outgrow it and early detection is the best way of avoiding additional complications. Usually aging is not a factor unless it is accompanied by a corresponding increase in the use of toxic substances such as alcohol or tobacco. Individuals with a family history of strabismus or amblyopia are more likely to suffer this condition.
Amblyopia is a relatively common condition, affecting approximately 4 out of every 100 people.
Q: What causes it?
A: Amblyopia occurs most commonly with misaligned eyes such as crossed eyes. The crossed eye "turns off" to avoid double vision, becoming lazy or amblyopic, and the child prefers the better eye. Amblyopia may also occur when one eye is out of focus because it is more nearsighted, farsighted or astigmatic than the other. The unfocused (blurred) eye "turns off" and becomes amblyopic. Sometimes the eye can look normal but one eye has poor vision. An eye disorder such as a cataract (a clouding of the lens which prevents light from being focused properly by the eye), may lead to amblyopia.
Q: What are the signs or symptoms?
A: Because amblyopia usually causes no symptoms, it often goes undetected. Unless the child has a misaligned eye or other obvious abnormality, there is nothing to suggest the condition to even the most perceptive parents. The child accepts having one good eye and one poor eye as the normal situation. In most cases, amblyopia must be detected through vision testing. A routine examination will determine if both eyes are being used and to what extent, and if each eye sees what it should. Consequently, the cause of the amblyopia can be identified and a treatment devised.
Q: How is it treated?
A: Before amblyopia can be treated, the underlying cause must first be determined and corrected. If it is due to crossed eyes, it may be necessary to surgically repair the muscles that control eye position and movement. If the amblyopia is due to a vision imbalance between the eyes, a corrective lens may be required for theweaker one.
Once the underlying cause has been identified and corrected, amblyopia is customarily treated by covering the good eye with a patch and forcing the weaker eye to work. If the weaker eye requires correction, eyeglasses are prescribed. Correcting amblyopia may require special glasses, surgery, patching of the eye or a combination of these methods.
Q: Can it be prevented?
A: In many cases, yes. Imbalance in vision between the eyes can be detected even in an infant, and once detected can be treated and corrected. Parents with a family history of strabismus should plan on eye examinations for their children during infancy.
Q: Can it always be corrected?
A: No! If too much time elapses, it may no longer be possible to teach the brain "to see" the images it receives from an eye it has never really used or used correctly. Generally, treatment must begin within the first five to six years of a child's life for there to be any chance of restoring vision.