December 24, 2010
Protect Your Sight This Summer
Every Australian child should learn to wear sunglasses outdoors to avoid the risk of vision loss later in life.
Researchers at The Vision Centre say there is strong scientific evidence that bright light harms our vision cells and cumulative damage causes loss of sight in old age.
However there are several steps which everyone can take to reduce the risk of long-term damage, they say. The earlier vision protection begins, the more effective it will be, says Professor Jan Provis, Associate Director and Chief Investigator of The Vision Centre.
"Australians are used to being told as children to cover up to avoid sun damage to the skin. The eyes are even more sensitive, as bright light damages photoreceptors, the key vision cells in our eye. However, the good news is that serious harm is avoidable."
Prof Provis says the best scientific advice at present is:
"¢ wear sunglasses as well as a hat from childhood onwards, whenever you go out into sunny conditions
"¢ minimise your long-term exposure to very bright light of all kinds
"¢ eat a healthy diet containing fresh vegetables, fruit and fish to maintain levels of antioxidants and other protective substances that affect eye health
"¢ take regular exercise to keep a blood pressure low, and
"¢ avoid smoking, drinking, drugs and other substances that may weaken the immune and cardiovascular systems, and this will also help protect the vision cells.
"It's a paradox that photoreceptors are designed to convert light into signals that the brain can recognize, but that exposure to strong light also damages them and can make them vulnerable to immune attack. This is a likely cause of age-related macular degeneration (AMD)" she says.
"Depending on your genetic background, you may or may not be equipped to cope with this sort of immune attack. The answer is to protect our eyes throughout our lifetime, and have a healthy lifestyle, to preserve visual capacity into old age.
"People who lose their sight late in life often depend entirely on others for all their daily needs. Unlike people who are blind from a young age, older people often find it too difficult to master the necessary skills for an independent life. Some spend years in this condition "“which may have been avoidable.
"Secondly, people tend to regard losing your sight as a normal part of growing old. Well, just as we can now keep our teeth much longer if we take good care of them, there is no need to lose vision either. There is plenty you can do personally to avoid outliving your eyesight."
Prof Provis said that other research carried out at The Vision Centre had found a certain amount of exposure to daylight was important in enabling the eyeball to develop normally in young children, and so prevent myopia. "The important thing is to establish a balance between too little exposure to light early in life and too much. Healthy outdoor activity is important for developing strong vision "“ but it is equally important to protect the eyes from very bright sunlight."
Prof. Provis said that cutting-edge research by scientists at The Vision Centre indicates that some visual damage sustained early in life may eventually prove reversible "“ though available treatments are probably still some years away and total blindness can probably only be corrected eventually by the development of a bionic eye.
"Evidence is accumulating that some damaged vision cells can recover function if the patient is kept in low light conditions.
"Vision Centre researchers are also currently exploring the use of near infra-red light, which reduces immune attack and has a healing effect on visual cells, in human patients for the first time.
"Also trials by Professor Silvia Bisti, of The Vision Centre, and colleagues have found the dietary herb saffron, which is high in certain antioxidants, can produce promising improvements in vision in human patients with age-related macular degeneration. (See Vision centre media release at http://www.vision.edu.au/news/Media%20Release%20DB/VC10_saffron_heals.pdf )
"Furthermore other researchers have shown that short doses of oxygen applied to the eyes under pressure can also improve vision, at least for a time."
However, she adds, more research needs to be done before any of these techniques can be perfected and approved for human treatment and "In the meantime, the message is to take good care of your vision, all your life."
The Vision Centre is funded by the Australian Research Council as the ARC Centre of Excellence in Vision Science.
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