Kids spend more time outside 'far less likely to become short-sighted'
Children who regularly play outdoors are less likely to become shortsighted as teenagers, a new study has revealed.
Previous research had linked time spent outside with good eyesight but researchers weren't able to prove whether it was due to exercise or exposure to natural light.
Lead author Dr Cathy Williams, of Bristol University, said that the study was the first direct evidence of benefits of natural light to the eyes.
The scientists said that there was a strong link between time spent outside and good vision, regardless of family history, how much time they spent reading or the child's physical activity.
They looked at eye tests from 7,000 children from Southwest England who were examined at the age of seven, ten, 11, 12 and 15. The team also monitored the children's physical activity over a week.
Those who regularly spent time outdoors at the age of eight or nine were half as likely to be short-sighted by the time they were 15.
"We're still not sure why being outdoors is good for children's eyes, but given the other health benefits that we know about we would encourage children to spend plenty of time outside, although of course parents will still need to follow advice regarding UV exposure," the Daily Mail quoted Dr Williams as saying.
"There is now a need to carry out further studies investigating how much time outside is needed to protect against short-sightedness, what age the protective effect of spending time outside is most marked and how the protective effect actually works, so that we can try and reduce the number of children who become short-sighted," she said.
Between a quarter and a half of children in the West and up to 80 percent of young people in parts of south-east Asia are affected by short-sightedness, or myopia.
More than a third of adults with the condition had to resort to wearing glasses in order to see distant objects clearly - a figure that has doubled over the last 30 years.
Previous research in Australia and the United States had suggested a link between the amount of time spent outside by children and their chances of needing glasses.
But the studies failed to show whether this was linked to exercise or simply being outside.
Dr Williams from Bristol and Jez Guggenheim of Cardiff University followed the occurrence of short-sightedness in over 7,000 boys and girls.
The youngsters, who all took part in the Children of the 90s study, were tested for short-sightedness at age seven, ten, 11, 12 and 15.
This was then compared with the amount of time they spent outside age nine and how much physical exercise they did age 11.
Those who spent more time outdoors before the ages of eight and nine were half as likely to become short-sighted at the end of the study. No such link was found with exercise when they were two years older.
Dr Peter Allen, College of Optometrists council member and Principal Lecturer and Director of Clinics at Anglia Ruskin University, said that Myopia, or short-sightedness, affects a significant number of people in UK.
"This research is particularly exciting because it's the first to identify that simply spending time outside - regardless of what outdoor activities you're engaged in - reduces the risk of becoming short sighted," he added.
The study was published in the journal Investigative Ophthalmology and Visual Science.