Children who spend more time outside 'are half as likely to become short-sighted'
Spending time outside in natural light reduced the risk of myopia in children whether they were active or not
15:01 GMT, 2 August 2012
Outdoorsy: Spending time in natural light has been linked with improving sight
Children who spend more time outside are less likely to become short-sighted, a study claims.
Researchers found youngsters who played outdoors between the ages of eight and nine were half as likely to develop short-sightedness when they reached 15.
The protective effect of being outside for longer is unrelated to whether children have parents who are short-sighted, or how much time they spend reading.
A team from the University of Bristol led the study, which is the first in the world to establish the direct link between poor eyesight and time enjoyed outside.
Study leader Dr Cathy Williams, said: '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.
'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.'
Between a quarter and a half of young people in the West and up to 80 per cent 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 need to wear 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 has previously 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 Cathy 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.
Indoor play: Short-sightedness has doubled over the last 30 years
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.
Other research has shown that a staggering 80 to 90 per cent of children in Asia are short-sighted – thought to be in part down to the large amount of time they spend indoors.
Dr Peter Allen, College of Optometrists council member and Principal Lecturer and Director of Clinics at Anglia Ruskin University, added: 'As a College we always welcome research that improves our understanding of eye health.
'Myopia, or short-sightedness, affects a significant number of people in UK so any findings that can help shed more light on why some people develop this and others don’t is hugely valuable.
'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.'
The study was published in the journal Investigative Ophthalmology & Visual Science.