The antioxidant properties of vitamins C and E, beta carotene and zinc were found to ward off macular degeneration, in which abnormal blood cells grow in the eye and leak blood and fluid that damage the center of the retina and blur central vision.

Sufferers are often debilitated and unable to read, recognise faces or drive, and the condition worsens with age. It affects more than one out of 10 white adults over the age of 80, and is the leading cause of severe vision loss in 60 and older.

There is no cure, although an earlier study found taking high doses of vitamin supplements could slow the condition's progression.

The eight-year study involved more than 4,000 older residents of Rotterdam, in the Netherlands. It found those whose diets included more than the median levels of vitamins C and E, beta carotene and zinc had a 35 percent lower risk of developing macular degeneration, compared with those whose diets provided a below-median level of any of the four nutrients.

Participants with a below-median consumption of all four of the nutrients had a 20 percent higher risk of macular degeneration.

"This study suggests that the risk of age-related macular degeneration can be modified by diet; in particular, by dietary vitamin E and zinc," wrote lead author Dr. Redmer van Leeuwen of the Erasmus Medical Center in Rotterdam.

"Foods high in these nutrients appear to be more important than nutritional supplements," he added in the report, published in this week's issue of the Journal of the American Medical Association.

Foods rich in vitamin E include whole grains, vegetable oil, eggs and nuts, the report said. High concentrations of zinc can be found in meat, poultry, fish, whole grains and dairy products. Carrots, kale and spinach are the main suppliers of beta carotene, while vitamin C is found in citrus fruits and juices, green peppers, broccoli and potatoes.

While the Dutch study showed a healthy diet was one of the keys to preventing macular degeneration, Dr. Carl Regillo of the Wills Eye Hospital in Philadelphia stressed the importance of early detection now that new treatments are available.