A cataract is a cloudiness or opacity in the normally transparent crystalline lens of the eye. Changes in the proteins, water content, enzymes, and other chemicals of the eye and lens are some of the reasons for the formation of a cataract. This cloudiness can cause a decrease in vision and may lead to eventual blindness.

Cataracts in the elderly are so common that they are thought to be a normal part of the aging process. Between the ages of 52-64, there is a 50% chance of having a cataract, while at least 70% of those 70 and older are affected. Cataracts associated with aging (senile or age-related cataracts) most often occur in both eyes, with each cataract progressing at a different rate. Initially, cataracts may not affect vision. If the cataract remains small or at the periphery of the lens, the visual changes may be minor.

Cataracts that occur in...