It is a normal condition of aging, generally resulting in the need for reading glasses. As people age, degenerative changes in the lens' proteins occur. Changes in the proteins, water content, enzymes, and other chemicals are some of the reasons for the formation of a cataract. The major areas of the lens are the nucleus, the cortex, and the capsule. The nucleus is in the center of the lens, the cortex surrounds the nucleus, and the capsule is the outer layer.
Opacities can occur in any area of the lens.
The density and location of the cataract determines the amount of vision affected. If the cataract forms in the area of the lens directly behind the pupil, vision may be significantly impaired. Cataracts in the elderly are so common that they are thought to be a normal part of the aging process. Initially, cataracts may not affect vision. If the cataract remains small or at the periphery of the lens, the visual changes may be minor.