My parents were right!! A spate of studies over the past decade has found that kids who spend more time outdoors are less likely to develop near-sightedness. Outdoor time seems to protect kids even if they do a lot of "near work" (e.g., reading Goosebumps and Animorphs nonstop) and if their parents are myopic.
When I was a kid, my parents would always tell me to stop reading and go play outside. I would scoff: What kind of parents want their kid to stop reading? But maybe they had a point after all.