Chicago ? Taking B vitamins can prevent a common type of vision loss in older women, according to the first rigorous study of its kind. It’s a slight redemption for vitamin supplements, which have suffered recent blows from research finding them powerless at preventing disease.

Age-related macular degeneration is the leading cause of blindness in people 65 and older, with nearly 2 million Americans in the advanced stage of the condition. It causes a layer of the eye to deteriorate, blurring the center of the field of vision and making it difficult to recognize faces, read and drive. There’s no cure, but treatment, including laser therapy in some cases, can slow it down.

Preventing it has been more elusive.

The women in the study who took a combination of B vitamins — B-6, folic acid and B-12 — reduced their risk of macular degeneration by more than one-third after seven years compared with women taking dummy pills.

The study, involving more than 5,000 women ages 40 and older at risk for cardiovascular disease, appears in Monday’s Archives of Internal Medicine.