These dietary supplements are the first effective treatment to slow the progression of the disease

Dr Paul Sieving

It reduced the risk of developing the advanced stages of the disease by about 25%, and the risk of vision loss by about 19%.

Researcher Dr Paul Sieving, of the US National Eye Institute, said: "This is an exciting discovery because, for people at high risk for developing advanced AMD, these dietary supplements are the first effective treatment to slow the progression of the disease."

Advanced AMD is a leading cause of visual impairment and blindness in people over 65. Current treatments are limited.

Dr Sieving said: "The supplements are not a cure for AMD, nor will they restore vision already lost from the disease.

"But they will play a key role in helping people at high risk for developing advanced AMD keep their vision."

Yellow deposits

A common feature of AMD is the presence of yellow deposits under the retina called drusen.

By themselves, these deposits do not usually cause vision loss, but an increase in their size and/or number increases the risk of developing advanced AMD, which can cause serious vision loss.

Advanced AMD is also associated with a either a breakdown of the light-sensitive cells and surrounding tissue of the retina, or leakage of the fragile blood vessels under the retina.

The antioxidant vitamins contained in the dietary supplements help to maintain healthy cells and tissues.

Another ingredient, zinc is an important mineral incorporated into many body tissues.

Previous studies have suggested that people who have diets rich in green, leafy vegetables have a lower risk of developing AMD.

However, the high levels of dietary supplements that were evaluated in the study are very difficult to achieve from diet alone.

Some people with intermediate AMD may not be able to take large doses of antioxidant supplements or zinc because of medical reasons. Some patients also reported minor side effects.

The research is published in the journal Archives of Ophthalmology.