It occurs when, for one of several reasons, one eye is used less than the other. If one eye is crossed or turns out, the individual sees double, so he or she learns to shut off or ignore that eye. If the two eyes are very different, one nearsighted and the other farsighted, the same thing can occur. After a while, vision in the unused eye is reduced.
For many years it was thought that amblyopia, or lazy eye when one eye sees poorly and cannot be helped with corrective lenses was a permanent condition unless it was detected and treated before the age of six. Many optometrists no longer accept this, believing that even adults can improve their sight – if not completely correct their lazy eye through special therapy.
Treatment varies depending on the extent of the condition, the patients age and the optometrist. Small children often have their stronger eye patched for several hours a day. This stimulates the use of the weak eye while they perform exercises such as coloring, cutting things out and tracing.
Vision therapy usually several hours a week, in the doctors office and at home will often correct the underlying reason for the lazy eye. Very small children can improve in a month or two; older children may take several months to a year to respond.
With adults, treatment is basically the same, but it takes longer. Adults may not wear a patch at all if vision is very poor, or only for an hour or two at home while doing fine tasks such as coloring in the 0s of a newspaper. Patients do exercises designed to improve focusing, tracking and spatial judgment.