New research has found a link between the amount of time children play outdoors and their chances of being short-sighted.
The data compiled from University of Cambridge studies involving more than 10,000 children and teenagers showed that for each additional hour spent outside per week, the risk of myopia (nearsightedness) is reduced by two per cent.
Nearsightedness is generally attributed to genetics, the amount of time spent focusing (reading) and levels of exercise, but Dr Justin Sherwin and his team found that short-sighted children spend, on average, 3.7 hours fewer outside than their 'normal-sighted' peers.
Dr Sherwin said: "It could be caused by not enough UV radiation [UV rays control the length of the eye] but it could also be spending less time looking into the distance or not enough physical activity."
He told the American Academy of Ophthalmology that there would need to be more research to understand which factors are most important, but warned that there were risks to advocating outdoor play.
"Any increase in time spent outdoors must be weighed against exposure to UV radiation - and the increased risk of skin cancer, cataracts and other cancers," he added.
"On the other hand, increasing outdoor physical activity could protect against diabetes and obesity, vitamin D deficiency and osteoporosis, for example."
Results were most striking for Chinese children, 80 per cent of east Asians are short-sighted (compared to 15 per cent in the UK) but the study showed that those living in Australian tended to spend more time outside and had better vision on average than their China and Singapore-based peers.
Eye specialist and surgeon, Dr Andrew Fink, said: "Genetic make up is a very important factor however environmental factors are also crucial.""[This research shows] that those who lead a rural, or predominantly outdoor lifestyle, have a lower prevalence of myopia than those who lead an urban lifestyle."
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Post uploaded 1300 October 26 2011 by Richard Hook