What Causes Cataract - Cataract: The Aging Eye Preventing And Treating Eye Disease

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What causes cataract?

Misconceptions abound when it comes to cataract. Contrary to what many people believe, cataract is not caused by cancer, or by a film blanketing the eye. It is not related to overuse of the eyes, and it does not spread from one eye to the other — though the condition may develop in both eyes.

Aging and accompanying changes in the chemical composition of the lens are the most common causes. Many cataracts develop as an exaggeration of normal aging sclerosis, in which the lens becomes less resilient, less transparent, and often thicker. Fibers in the lens become compressed, and the lens becomes more rigid. Clarity fades as proteins coagulate, or clump together, creating tiny specks or wheel-like spokes in the periphery of the lens. In later stages, the milkiness becomes denser and occurs in the center, making it truly difficult to see. The change in the lens is similar to what happens when you cook an egg white; it goes from clear to opaque. Other cataracts begin developing at the center of the lens, causing nearsightedness before opacity and distortion. According to clinical studies, more than 40% of people in their 50s to early 60s already have some sclerosis in their lenses.

Though age is the factor most likely to cause cataract, other factors such as heredity, eye injuries, use of some medications (particularly corticosteroids), and certain health problems (such as diabetes) may contribute to cataract as well. Several studies have linked cataract with alcohol consumption and smoking. Even if you have smoked for many years, quitting now will help you avoid cataract in the future. Long-term exposure to high levels of ultraviolet-B (UVB) rays from the sun is another hazard, and studies have found a greater prevalence of cataract in people who live in areas with considerable sunlight.

Last updated:	June 19, 2007