ANTI oxidant dietary supplements can prevent macular degeneration, a common form of age related blindness which affects 37 per cent of people over the age of 75, says the Journal of the American Optometric Association. In this painless, progressive condition, a circular blind spot develops in the centre of the field of vision, big enough to block out two or three words at a time on a page. In a major study, elderly veterans took non prescription antioxidant capsules containing 14 components, including zinc and vitamins C and E, thereby halting the progression of the disease.