Cataracts are responsible for about 30 to 50 million cases of blindness throughout the world. Cataract increases with age, reducing visual acuity and constituting a major cause of disability in the elderly, according to the researchers.

The team investigated the effect of long-term antioxidant supplementation, testing both lutein and alpha-tocopherol (or vitamin E), on serum levels and visual performance in seventeen patients with cataracts. They found that the patients' eyesight improved with both nutrients, although most significantly with lutein supplements.

The patients were randomised in a double-blind study. They took either 15mg of lutein, 100mg of alpha-tocopherol, or a placebo, three times a week for up to two years. Serum carotenoid and tocopherol concentrations were measured, and visual performance (visual acuity and glare sensitivity) was monitored every 3 months throughout the study.

The authors noted: "Serum concentrations of lutein and alpha-tocopherol increased with supplementation, althoughstatistical significance was reached only in the lutein group." Visual performance (visual acuity and glare sensitivity) improved in the lutein group, but with Vitamin E it remained at the same level and it decreased in those taking placebos. They reported no significant side effects in any of the subjects during the study.

The researchers say the results suggest that a higher intake of lutein, through lutein-rich fruit and vegetables or supplements, may have improve the visual performance of people with age-related cataracts.

The study was published in the January 2003 edition of the journal "nutrition".