Teasing Out Causes of Cataract


SCIENTISTS HAVE long assumed that cataracts are a product of old age and environmental factors like smoking, diet, and sun exposure. But researchers from a London hospital say your genes may figure more prominently than your age or your habits in the risk for cataract formation.

In comparing cataracts in 506 sets of twins, the scientists found that genetic makeup explained differences in cataract severity more often than any other factor--almost 50 percent of the time. Age was to blame in 38 percent of cases, while lifestyle factors accounted for just 14 percent.

That's not to say that quitting smoking, staying out of the sun, or changing your diet is useless. Those lifestyle modifications could be what tip the balance in many people. "It may be that environmental factors become more important in individuals who already have a genetic susceptibility to cataracts," says ophthalmologist Christopher Hammond, FRCOphth, who led the study. Indeed, evidence abounds that smoking and ultraviolet rays from sunlight are both damaging to eye health. And diets high in vitamin C as well as in lutein and zeaxanthin, compounds in dark green leafy vegetables, have been linked with reduced risk of cataracts in some studies.

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