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Thursday, June 23, 2011

Sight and Sunlight

There are so many good reasons for kids to go outside in the summer. That's where the lakes, rivers and playing fields are. It's so much easier to swim, kayak or run outdoors than in the living room. And it's so much harder to develop juvenile obesity, or diabetes.

Besides which, there now appears to be another reason to get kids out of the house. Exposure to sunlight may make them less myopic. Just 1/4 of Americans were nearsighted in the 1970s, but more than 40% of us are nearsighted now.  Why is that?  Because we're spending more time under artificial lights.
Natural light helps a child's developing eyes maintain a correct distance between the developing retina and lens. That keeps vision in focus.  When a child spends too much time indoors, the distance between the lens and retina becomes too long.  So faraway objects start to blur.
Kids in Singapore, who are outdoors just 3 hours a week on average, are 9 times more myopic than kids in Sydney, who spend an average of 14 hours a week outside.  And among American children with 2 myopic parents, those who spend at least 2 hours a day outdoors are 4 times less nearsighted than those who spend less than an hour a day outside.
Human brains, like human bodies, have been wired to spend time on lakes, rivers or fields.  And summer vacation is a good time to get out of the house.