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More Time Outside Tied To Less Nearsightedness In Children
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."
The "always look at the thing in your hand" generation is completely screwed...
Excuse me while I go buy stock in glasses retailers and Lasik providers.
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.
As someone with a glasses fetish, I'm OK with this.
Still bitter that my wife got herself Lasik correction way back when, though. Even moreso that she did it without using pretax HSA dollars.
Came to this conclusion myself a while back due to how much time I spent in front of a computer compared to my sisters. Definitely has an effect on you.
I think the idea is to spend more time outside rather than in front of your sisters.
Wir sind geboren, um frei zu sein - Rio Reiser
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.
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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?
You are welcome on my lawn.
Your eyes keep growing until you're a teenager. Most of it happens in the first few years.
There seems to be some incorrect information around that says the opposite though, that you're born with adult sized eyes.
Things grow in response to usage. If you never try to touch your toes are you grow, you'll find that you don't have the flexibility to do it later in life, and it's extremely difficult to regain that flexibility.
Why would the muscles and structures in your eyes be any different?
From here:
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
The "always look at the thing in your hand" generation is completely screwed...
Well in slashdot users case, they at least know what their pecker looks like.
they know it on a ....... first hand basis.
The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.