Don't study too much... or you'll go blind :>

'' East Asia's nearsighted-child epidemic: Is over-studying to blame?
A new study finds that a shocking 90 percent of schoolkids in Asia's obsessively school-focused big cities have myopia 
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In most Western nations, 20 to 40 percent of children have myopia, the technical term for nearsightedness. In the cities of East Asia, that number jumps as high as 90 percent, according to a new study in the British medical journal The Lancet.

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In the major cities in Japan, China, South Korea, Taiwan, Hong Kong, and Singapore, 80 to 90 percent of teens had myopia upon leaving high school. More worrisome, 10 to 20 percent of the high school grads were afflicted by high myopia, a more serious strain that can lead to blindness. The main problem, say the researchers, is lack of exposure to sunlight.

'' [source]