Reducing risk of myopia

Writing in the Los Angeles Times (1/12) Booster Shots blog, Shari Roan observed that, according to a study published in the Jan. issue of the journal Optometry and Science Vision, "spending two or three hours outdoors each day appears to lower a child's risk of developing" myopia, a condition that "affects about one-third of U.S. adults." In analyzing "several large studies examining nearsightedness...in large populations," researchers found that "the risk of myopia drops in
children who spend more time outdoors." Yet, "the authors of the analysis say they cannot explain why outdoor time lowers the risk of nearsightedness. It could be related to more time spent on distance viewing or to being in sunlight."

"The critical factor for reducing the development of myopia in children seems to be total time spent outdoors during daylight hours," and not what the children are doing outside, UPI (1/13) points out. In fact, "both active and passive outdoor activities had a protective effect on vision, while sports played indoors were found not to have this effect." Donald Mutti, guest editor of the journal, explained that "a child's chances of becoming myopic -- if he or she has two myopic
biological parents -- are about six in 10 for children engaging in zero to five hours per week of outdoor activity, but the risk drops to two in 10 when outdoor activity exceeds 14 hours a week."