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Medicine

More Time Outside Tied To Less Nearsightedness In Children 60

Bookworm09 writes: For primary school children in China, spending an extra 45 minutes per day outside in a school activity class may reduce the risk of myopia, according to a new study. In some parts of China, 90% of high school graduates have nearsightedness, and rates are lower but increasing in Europe and the Middle East, the authors write. "There were some studies suggesting the protective effect of outdoor time in the development of myopia, but most of this evidence is from cross-sectional studies (survey) data that suggest 'association' instead of causality," said lead author Dr. Mingguang He of Sun Yat-sen University in Guangzhou. "Our study, as a randomized trial, is able to prove causality and also provide the high level of evidence to inform public policy."
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More Time Outside Tied To Less Nearsightedness In Children

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  • Its better eye exercise to be active outside, where your focal range is much greater and you are changing focal points much more often than when inside.
    • by Anonymous Coward
      Since it's so obvious to you, which part of the eye is being strengthened by exposure to varying focal ranges?
      • Re:Makes sense (Score:5, Interesting)

        by ChrisMaple ( 607946 ) on Wednesday September 16, 2015 @07:13PM (#50537009)

        It isn't a question of strengthening. It's a question of the shape of the eye's lens and the distance from the lens to the retina.

        It's a matter of controversy (although it shouldn't be) which of the two is usually misshaped in myopia.

        Being outside means that most of the time the eye will be focused near infinity, and that habitual condition is what helps prevent myopia.

        There are other factors involved with being outdoors in sunshine.
        ____Sunshine causes the generation of vitamin D. So far as I know, this does not affect myopia.
        ____There's proportionally more blue light outdoors. Blue is refracted more strongly (the eye is not an achromat), so to get overall better focus when there's a strong blue component in the light, the eye must focus less strongly, i.e. farther away. This improves the habitual state of the eye.

        There is a claim (among the advocates of the Bates system) that muscles can be used both to focus nearer and farther away, but conventional understanding of the eye's focus mechanism is that muscles are used only to swivel the eyes and to make them focus near. Far focus is the relaxed condition.

      • When you're a kid, your eye is still growing. Myopic people suffer from an eye that is basically too long--the retina is too far from the lens and the lens will focus in front of it when the target is any distance away. It makes sense that never focussing on the distance encourages the eye to grow this way. It adapts to short focussing distaces.

  • My eye sight (and weight) starting going bad after college. I figure it was because I was spending more time sitting down and staring at a computer when I got my first desk job than before (where I used to usually sit at the computer only at home or at a class per semester).
    • My eye sight (and weight) starting going bad after college. I figure it was because I was spending more time sitting down and staring at a computer when I got my first desk job than before (where I used to usually sit at the computer only at home or at a class per semester).

      Weird thing is, in the last 5 years, my eyes have become radically better. TO the point where my wife insisted I get them checked, in case of some inknown problem. But I can now drive without glasses, and my close vision is much better since I don't have to wear glasses that correct the far vision much at all any more.

      • What did you change? i'd like to know.... can I buy some of your snake oil? :)
        • What did you change? i'd like to know.... can I buy some of your snake oil? :)

          Its the craziest damn thing. No one knows, but after mulltiple checks, there's no problem, just that anomaly.

  • by Spy Handler ( 822350 ) on Wednesday September 16, 2015 @06:21PM (#50536623) Homepage Journal

    This article basically confirms it, but the topic was covered extensively in the health media last year. I don't remember the study but they noted that white anglo population in England had a much higher rate of myopia than the white anglo population in Australia. Australians get a lot of sunshine, England is cursed with a lot of fog and rain. Genetics is not a factor since the two populations are virtually identical with only ~100 years separating them.

    Anyways the key factors are light and focus. Bright lights (such as sunlight) = healthy eyes. Time spent with eyes focused on close objects (such as reading or computering) = myopia. Of course spending time outdoors on a sunny day leads to eyes exposed to high levels of light and focused on distant objects, while playing Gameboy indoors will lead to the opposite.

    Note that this effect concerns growing children. Adults already have their eyeball shape pretty much fixed and it's rare to develop myopia in adulthood.

    Anyways my point was that it's not necessarily outdoors that prevents myopia in children, it's light and focal distance. So if a child were to spend all their time indoors but the house was brightly lit and a lot of that time was spent watching a TV far away (like 6 meters or more), they won't develop myopia. Of course that's hard to do since most house lights are nowhere near bright enough to match sunlight levels, and if you're indoors it's hard to keep your eyes focused far away for extended periods.

    • or.... lots of sunshine means kids spend more time outdoors, lots of rain and fog mean kids spend more time inside. So it could still be outdoor activity that helps prevent myopia and good weather increases outdoor activity.

    • Of course that's hard to do since most house lights are nowhere near bright enough to match sunlight levels,

      Skylights. If your ceiling is too far from the roof, use a light tube. I'm opposed to widespread adoption of PV solar because its levelized cost is still several times higher than other electricity sources. But skylights are obvious. It makes no sense to deliberately create shade with a roof, then use artificial lighting to get rid of the shade.

      and if you're indoors it's hard to keep your eyes f

    • by jrvz ( 734655 )
      "Time spent with eyes focused on close objects (such as reading or computering) = myopia." RIGHT.

      How it's supposed to work: Child is born farsighted -> much time spent outside looking at distant objects, but focusing muscles in the eye can still bring those objects into focus -> muscles get tired -> brain concludes "I'm still farsighted" -> eyes grow -> eyes can relax most of the time - i.e. while looking at distant objects = perfect vision.

      How it's working in industrialized countrie
  • and I could have kept up the self abuse without going blind
  • In other words, the smartness gene causes both nearsightedness and a decreased desire to play outside.
  • ...that if you spend all your time as a kid never focussing on anything more than six feet away, you'll most likely wind up near sighted.

    • Will only work with very well behaved kids, but you could make them wear reading glasses while reading and using a computer.

      Problem solved.

  • Mr Magoo (Score:5, Funny)

    by PopeRatzo ( 965947 ) on Wednesday September 16, 2015 @07:36PM (#50537167) Journal

    Are you telling me that all those times my mom yelled, "Don't sit so close to the TV, you'll ruin your eyes!" she was right?

    • by AmiMoJo ( 196126 )

      This is my biggest regret about childhood. Didn't look after my eyes or ears. The damage isn't too bad, fortunately.

  • by TheSync ( 5291 ) on Wednesday September 16, 2015 @08:09PM (#50537359) Journal

    From here [nature.com]:

    In 2009, Regan Ashby, Arne Ohlendorf and Frank Schaeffel from the University of Tubingen's Institute for Ophthalmic Research in Germany showed that high illumination levels - comparable to those encountered outside - slowed the development of experimentally induced myopia in chicks by about 60% compared with normal indoor lighting conditions

    The leading hypothesis is that light stimulates the release of dopamine in the retina, and this neurotransmitter in turn blocks the elongation of the eye during development. The best evidence for the 'light-dopamine' hypothesis comes - again - from chicks. In 2010, Ashby and Schaeffel showed that injecting a dopamine-inhibiting drug called spiperone into chicks' eyes could abolish the protective effect of bright light

  • by koan ( 80826 )

    And more likely to get cataracts later in life.

  • ... when I was one or so -- because my mother war a bit paranoid, as she had had lots of eye trouble as an infant and I was child no. 1/ The doctor looked at my eyes and told her I had almost perfect vision -- which was actually bad, because it is normal for young children to be far-sighted. One's eyeball gets longer as one gets older, so while "normal" kids eyes would go from far-sighted to normal, my eyesight was fated to go from normal to VERY near-sighted. He was right.

  • Every single person on both sides of my family wears glasses. Both my parents, my brother, 20 or so cousins, and all aunts and uncles and grandparents wear glasses. I have 20/15+ vision that far exceeds normal vision. For example I can read a Burger King menu from the play center. How do I explain it? I was always focused at a static depth so how could my lenses or whatever have warped? I did go outside a lot but percentage-wise, it was TV and computers.
  • Though I'm told staying up half the night reading Analog and not having my eyes equidistant from the pages is what doomed them.

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