Slashdot Mirror
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.