Cataracts are a deterioration of the natural lens, which becomes progressively cloudy, milky, yellowish or brownish.  Cataracts prohibit and block light passing through to the retina, which result in unclear vision.

Most cataracts occur in people over 60 years of age and can be found in one eye or both eyes. In most people, cataracts are developed due to the clouding of the lens by a natural aging process. However, cataracts may also be found in younger ages due to other causes such as exposure to ultraviolet rays, severe eye injury, smoking, long-term use of steroid medications or various congenital diseases such as diabetes and high blood pressure.

There are many stages of cataracts. In the early stages, cataracts do not affect lens clarity much, if at all. During these stages, lenses still remain mostly clear, but patients may find themselves with increased nearsightedness and/or astigmatism, and may require glasses or contact lenses.

Cataracts which result from the aging process of the eye are a normal phenomenon and affect everyone.