Repeated studies reported in the journal Optometry and Vision Science have shown that outdoor play improves distance vision and lowers the chance of nearsightedness. And in an Australian study from the University of Sydney released in April, researchers found narrowed vessels in the retinas of children who spent the most time sitting in front of a TV or playing video games, a condition that could point to heart disease risk.

The children in the study who spent more time running and playing outside had the healthiest blood vessels in their retinas. You can read more about the Australian study in Science Daily http://www.sciencedaily.com/releases/2011/04/110420164419.htm