December 1/London/Daily Mail -- A diet rich in oily fish could hold the key to preventing blindness among thousands of the elderly, research has found.

The omega-3 group of fatty acids, found in oily fish such as salmon, mackerel and fresh tuna, may help protect against the most common form of sight loss among older people, it suggests.

Scientists studying the diets of adults over the age of 65 found those who regularly ate seafood were far less likely to develop age-related macular degeneration (AMD), which is caused by the death of cells in the retina.

There is currently no cure for the condition, which affects almost a third of Britons over the age of 75.

It gradually causes sufferers to lose their "central vision," meaning they can no longer see what is directly in front of them, making activities such as reading, writing, driving and watching television almost impossible.

Almost 240,000 people in Britain are thought to suffer from some form of visual impairment caused by AMD.

In the study, American scientists surveyed 2,400 volunteers aged 65 to 84. Those who ate oily fish or shellfish -- particularly crab, oysters or mussels -- twice a week or more often were far less likely to have AMD, the results in the Ophthalmology journal, revealed.

It is thought that the omega-3s may help protect cells in the retina from damage caused by sunlight, which occurs gradually with age.

The research at Wilmer Eye Institute at the Johns Hopkins School of Medicine in Maryland backs up earlier studies which showed omega-3s help slow the progression of advanced AMD.

Lead researcher Dr Sheila West said, "'While participants in all groups, including controls, averaged at least one serving of fish or shellfish per week, those who had advanced AMD were significantly less likely to consume high omega-3 fish and seafood."

From the December 20, 2010, Prepared Foods E-dition