Likely improves their eyesight too. South Korea has most of its population wearing glasses for nearsightedness. http://www.nature.com/news/the-myopia-boom-1.1

Likely improves their eyesight too. South Korea has most of its population wearing glasses for nearsightedness. http://www.nature.com/news/the-myopia-boom-1.17120 http://www.nature.com/news/the-myopia-boom-1.17120 "Sixty years ago, 10–20% of the Chinese population was short-sighted. Today, up to 90% of teenagers and young adults are. In Seoul, a whopping 96.5% of 19-year-old men are short-sighted." It seem likely that environmental factors (housing/education) are dominant. If you placed young Korean children in wide open spaces to the extent they now spend indoors, the trend would likely reverse. Outdoor classes in a big green park sound like fun.