weird things start happening to our eyes in the absence of outdoor space and light. One clue was a study from China that found twice the rates of myopia (nearsightedness) in wealthier, urban parts of the country than in rural areas. In Shanghai, a stupendous 86 percent of high school students need eyeglasses. As recent studies in Ohio, Singapore and Australia found, the real difference between those with myopia and those without is the number of hours they spend outside.
