Myopia (nearsightedness) occurs because the clear front cover of the eye (cornea) has too much curvature. As a result, light entering the eye focuses incorrectly, making distant objects look blurred. While there is evidence that this “refractive error” is hereditary, there is research indicating that performing too much close-up work may also influence myopia development. Because myopia is reaching epidemic proportions among children in urban areas of the East and Southeast Asia in particular, Chinese researchers sought to see what difference it might make to add one 40-minute outdoor session to young school children’s days. After three years, those playing outside regularly realized a 23% reduction in the development of myopia over children who didn’t get the extra outdoor time.
P.S. Being outdoors may help children focus their vision more on long distances, thereby reducing the incidence of myopia.