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Amblyopia ( "am-blee-oh-pee-ah") is the medical term for poor vision in one, or sometimes both eyes.

It is generally caused by lack of use of one eye when the brain "favors" one eye over the other. In most cases, the eye itself is healthy but is different in some way to cause this preference.

The most common forms of amblyopia are strabismic and anisometropic. Strabismic (also called "crossed or turned eye") amblyopia occurs when a strabismus is present and the eyes are not aligned. The brain favors one eye over the other, the non-preferred eye is not adequately stimulated and the visual brain cells do not mature normally. Anisometropia refers to the condition when the eyes have an unequal "refractive power". One eye may be nearsighted and the other is farsighted. Because the brain can not "balance" this difference, it picks the eye that is "easier" to use and develops a preference for this eye only.

Good eyesight requires a clear, focused image that is the same in both eyes. If the image isn't clear in one eye, or if the image isn't the same in both eyes, the vision pathways won't develop properly. The vision pathways in the brain must become strong early, when children are very young. The first few years of life are the most important for eyesight. After a child is 8 to 10 years old, the brain's visual development is complete.

Because there are several causes of amblyopia, the treatment must match the problem. Glasses fix problems with nearsightedness, farsightedness and/or astigmatism. Surgery may be needed for cataracts, droopy eyelids or crossed eyes. After the cause of the amblyopia is found, the child will need to use the weaker eye, so it will get stronger. To make the child use the weaker eye, a patch is put over the stronger eye. Patches may be used all day or part of the day, depending on the child's age and vision. Sometimes, eye drops or special glasses are used to blur the vision in the stronger eye. This makes the weaker eye become stronger. The treatment must continue until vision is normal, or until vision stops getting better.

In most cases amblyopia is treatable. However, the success of treatment is dependent upon the initial level of vision, the amount of time the vision has been poor and the age of the child.

The most important factor in treating amblyopia is compliance with the treatment protocol. The initial treatment period may be difficult for the child, as he/she is being made to use their "bad" eye. This usually lasts a short period of time, as their vision improves rapidly. It can not be overemphasized that the major reason for failure in the treatment of amblyopia is poor compliance with the treatment protocol. Remember, amblyopia can be treated only when a child is young. If it is delayed until the child is older and more understanding, it may be too late!