News and Events

Cataract Risk and Exposure to Sunlight

National Eye Institute
National Institutes of Health

Researchers report in the August 26, 1998 issue of The Journal of the American Medical Association (JAMA) that exposure to UV-B radiation from sunlight can increase the risk of cataracts in people who have had fairly low exposure to sunlight throughout their lifetime.

A cataract is a clouding of the eye’s lens that can interfere with vision. In its early stages, a cataract may not cause a problem. However, over time, the cataract may grow larger and cloud more of the lens, making it harder to see. The most common types of cataract — nuclear, cortical, and posterior subcapsular cataracts — are related to aging. More than half of all Americans age 65 and older have some evidence of cataract, with nuclear and posterior subcapsular cataracts responsible for most of the approximately 1.5 million cataract surgeries annually in the United States. Unlike nuclear and posterior subcapsular cataracts, cortical cataracts do not usually affect central vision because they usually develop on the outer edge of the lens.

The new findings were reported by Sheila West, Ph.D., professor of ophthalmology at the Johns Hopkins Wilmer Eye Institute, and her colleagues. These findings support several previous studies associating UV-B radiation exposure and cortical cataract. This association with cortical cataract appears to be present even among people with relatively low levels of UV-B radiation exposure. However, the authors report no association between sunlight exposure and either nuclear cataract and posterior subcapsular cataract.

Although UV exposure to the eyes seems to explain only a small part of the risk of developing sight-threatening cataracts, the study’s suggestion of wearing sunglasses that block UV light and/or a hat with a brim could help reduce UV light exposure.

This study was supported by the National Institute on Aging, part of the Federal Government’s National Institutes of Health.

August 25, 1998