Amblyopia, commonly known as “lazy eye” is a condition where one eye is used less than the other. In most cases of amblyopia, both eyes are completely normal in shape and structure. The problem begins in early childhood and for reasons described below, the vision from one eye gets “shut off”. As this “shutting off” of one eye continues through childhood, the eye gets used less and less until the person cannot see normally, even with glasses or contacts. This would be similar to placing a baby’s arm in a cast for years; if the arm is not used during childhood, its function will suffer.
Why does Amblyopia occur?
Amblyopia usually occurs if the eyes cross or if one eye turns outward towards the ear. When the eyes don’t line up properly, double vision can occur. In order to cope with the double vision, the brain ignores or suppresses the information coming from the eye that is pointed in the wrong direction.
Amblyopia can also develop if a child is highly farsighted/nearsighted in one eye and normal sighted in the other eye. If this is the case, the person is left with the problem of trying to blend together a clear image and a blurry image. Similar to double vision, this situation is intolerable to the child so he/she learns to suppress the information coming from the poorer seeing eye.
Treatment for Amblyopia
The treatment for amblyopia varies based on the patient’s age, severity of the condition and the glasses prescription strength. In some cases, amblyopia is treated successfully with glasses alone. In other cases, a patch is used for several hours of the day. While wearing the patch, the patient is usually directed to draw, color, cut with scissors and perform other “eye-hand” activities.
The treatment with patching described above usually helps the function of the poorer seeing (amblyopic) eye but doesn’t ensure that both eyes will work together as a team when the treatment is finished. Sometimes after the treatment, the amblyopia returns if the person isn’t trained how to use the two eyes together (binocular vision).
In order to train both eyes to work together, vision therapy may be required. Vision therapy usually consists of weekly, hour long office sessions with an additional home therapy training.
Regardless of the type of treatment selected, vision can improve in as little as a few months for small children. Older children and adults typically take longer to respond.