Regular orange eaters are 60 per cent less likely to have developed the disease 15 years later, a new research study has discovered.

People who eat an orange a day are the least likely to suffer from macular degeneration when they're elderly, but even eating an orange once in a while also has some protective effect.

Although vitamins C, E and A are supposed to be keep our eyes healthy, it was the flavonoids specifically found in oranges that seemed to have the greatest benefit, say researchers from the University of Sydney.

Eating between 100 and 142 mgs of vegetable nitrates—found in leafy vegetables and beetroot—every day reduces the risk of developing AMD by around 35 per cent.

Spinach contains 20mg of nitrate, and beetroot has 15mg, per 100g serving.