FIGURE 2.13 Go Out and Play! If both your parents are nearsighted, chances are you will be, too—but not if you play sports at least six hours a week. The dramatic correlation between childhood myopia and playing sports does not prove causation: Some children who wear glasses choose to avoid sports. Nonetheless, parents and schools should encourage children to play outside every day. In 2010, only about 64 percent of all children did so, a 10 percent decline over the course of 10 years.