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...