Smoke Gets in Your Eyes

Cataracts are by far the world's leading cause of blindness, causing visual impairment in more than 3 million people in the U.S. and 50 million globally. Americans alone undergo about a million operations a year to have clouded lenses removed from their eyes. A pair of major studies in J.A.M.A. (Journal of the American Medical Association) has now concluded that 20% of those cases may be caused by an activity already implicated in cancer, stroke and heart disease: cigarette smoking.

Earlier studies hinted that cataracts are associated with smoking, along with other factors, including exposure to ultraviolet light and the use of steroids and alcohol. But this is the strongest evidence yet. Researchers monitored nearly 18,000 male physicians and more than 50,000 female nurses for five and eight years respectively, asking about smoking behavior and checking the incidence of cataract surgery. The conclusion: men who smoked more than a pack a day ran twice the risk of nonsmokers for developing lenses cloudy enough to require their removal; women who so indulged had a 60% greater risk than their abstemious counterparts. Both men and women lowered their chance of developing cataracts if they stopped smoking -- but still got them more often than those who never smoked.

The actual mechanism by which smoking induces cataracts is still unclear. One theory argues that blood is starved of important nutrients. But that's just a guess; more certain is that there is now yet another good reason not to smoke.