2015年4月24日星期五

Lack of natural sunlight thought to be driving up short-sightedness among young

  • Researchers had thought reading or looking at screens caused condition
  • But now believe it could be because both of these activities occur indoors
  • Forty minutes extra of natural light per day could cut cases by a quarter
  • Chinese children now being sent to schools with translucent walls 

Climbing trees and spending hours playing outside used to be part of every childhood. But today’s youngsters are more likely to be stuck indoors – and it may be harming their eyesight.

And it is not just because of the time spent sitting in front of a screen. For a lack of natural daylight is thought to be driving up rates of short-sightedness among the young.

Spending an extra 40 minutes a day in the sunshine has been shown to improve children’s sight dramatically.

Scientists had though reading or looking at a screen could cause shortsightedness, but now think it could be down to a lack of natural light while taking part in these activities (file image)

Scientists had though reading or looking at a screen could cause shortsightedness, but now think it could be down to a lack of natural light while taking part in these activities (file image)

In China, where four teenagers in five are short-sighted, transparent classrooms are being tested in a bid to increase pupils’ exposure to natural light.

Chinese scientists have reported a 23 per cent reduction in myopia – short-sightedness – in children who spend an extra 40 minutes a day in the sunshine. 

Studies in Australia and by Ohio State University in the US produced similar results.

Leading eye surgeon David Allamby warned that an increase in eyesight problems is likely in Britain if children do not regain a love of the great outdoors. 

Two in five adults in this country are short-sighted, but Mr Allamby said those rates are likely to increase.

‘For 100 years we have researched into the effects of reading and prolonged study on making short-sightedness worse,’ he said. 

‘It has become a common belief that spending too much time inside a book, or today on a screen, will make anyone’s eyesight worse.

‘Recent research might have turned this on its head. That’s why today some Chinese schoolchildren are going to school inside a big glass box. 

There are several studies showing that lack of daylight might be the principal reason why children become more short-sighted, rather than prolonged reading. 

Study shows that 40 minutes of extra natural light per day, by playing outside or climbing trees, could help to reduce cases by 26 per cent (file image)

Study shows that 40 minutes of extra natural light per day, by playing outside or climbing trees, could help to reduce cases by 26 per cent (file image)

'What wasn’t factored into our decades of research was that reading and studying are done indoors, away from daylight.

‘The link between studying and myopia might really be a red herring, where the close vision activity is just a proxy for lack of daylight.’

Donald Mutti, who led the Ohio study, told the journal Nature: ‘We thought it was an odd finding but it just kept coming up as we did the analyses.’

Mr Allamby, who runs Focus Clinics in London, said: ‘The incidence of short sight in the West is rising, now affecting around 40 per cent of the population.

‘If we look at hunter-gatherer societies that live mainly outdoors, such as those studied in Gabon, we find that only 0.5 per cent of adults are afflicted by short sight.

‘Chinese children are participating in research to determine if more exposure to daylight will protect them from their myopic genes.

‘If [it] is shown to help it might mean we all got outdoors more often. It could be time to invest in conservatory companies.’

 



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