Many cataracts take years to develop to the point where vision
is seriously affected. Most occur as a result of the normal
aging process. The types of age-related cataracts are usually
described by their location in the lens. They are: nuclear
cataracts, cortical cataracts and subcapsular cataracts. Nuclear
cataracts occur in the center of the lens and may induce other
eye problems, such as myopia. A cortical cataract, which tends
to occur more in persons with diabetes, begins at the outer
portion of the lens, then slowly moves inward. Subcapsular
cataracts develops under the capsule, often at the back of the
lens. This type of cataract also occurs more in persons with
diabetes, but it is also found in persons with high myopia,
adults with retinitis pigmentosa and in people who take
steroids.