The time children spend outdoors could be linked to a reduced risk of being short-sighted, research suggests.    An analysis of eight previous studies by University of Cambridge researchers found that for each additional hour spent outside per week, the risk of short-sightedness was reduced by 2%.They said exposure to natural light and time spent looking at distant objects could be key factors .    The studies involved more than 10,000 children and adolescents. Dr Justin Sherwin and his research team concluded that short-sighted children spent an average of 3.7 fewer hours per week outdoors than those who either had normal vision or were far-sighted.    But they said the reasons were not yet clear.They expected to find that children who spent more time outdoors also spent less time doing activities like reading, studying or playing computer games, but no such link was found in two of the eight studies which looked at this relationship.    However, Dr Sherwin said they would now need more precise data to try to understand which factors,  such as increased use of distance vision, reduced use of near vision, natural ultraviolet  light exposure  and physical activity,are most important.    "Any increase in time spent outdoors must be weighed against exposure to ultraviolet radiation and the increased risk of skin cancer, cataracts and other cancers."he said."On the other hand, increasing outdoor physical activity could protect against diabetes and obesity, for example."     Short-sightedness is a common eye condition that causes distant objects to appear blurred , while close objects can be seen clearly. It is much more common today in the UK and the United States than it was just 30 to 40 years ago. Approximately 1-2% of five-year-olds to seven-year-olds in the UK have short-sightedness.About.five million British people are short-sighted and some 200,000 of them will be seriously short-sighted. In some parts of Asia, more than 80% of the population suffers from short-sightedness. Which of the following is TRUE?
Students who spent more time outdoors read less Only one factor contributes to short-sightedness The increase in time spent outdoors means more exposure to ultraviolet radiation The less time children spent outdoors, the more short-sighted they are