Go out and play! It’s good for your eyes

Yet another reason for teens to get off the screen and into the great outdoors: Sunlight can help ward off nearsightedness, according to a study published Thursday.

Although too much sun can lead to skin cancer, exposure to ultraviolet B (UVB) radiation as a teen or young adult may be good for the eyes, reducing the chance of developing the world's most common eye disorder.

Researchers found UVB exposure between the ages of 14 and 29 years was associated with a significant decrease in the chance of developing nearsightedness as an adult, according to the study, which appeared in the peer-reviewed Journal of the American Medical Association -Ophthalmology. 

Nearsightedness has increased dramatically in the U.S. and around the world in the past few decades. A 2009 study from the National Institutes of Health found the number of nearsighted Americans ages 12 to 54 grew from 25% in the early 1970s to 41.6% in the early 2000s.

Scientists involved with the new study gave medical exams and gathered medical histories from about 3,000 Europeans ages 65 and older, of which about 10% were nearsighted.

Those who indicated they had the most exposure to UVB as teenagers and young adults were roughly 30% less likely to develop nearsightedness later in life compared to those with the least exposure. However, researchers did not uncover a clear explanation for the finding.

"Spending time outdoors is protective, but the mechanism underlying this association is poorly understood," the study said. While people get a boost of Vitamin D after being in the sun, a link between Vitamin D levels and nearsightedness was not found, researchers said.

This study also found that those who were more educated were more likely to develop nearsightedness. The possible cause of that finding was also not detailed in the report.

Kimberly Yen, a pediatric ophthalmologist at Texas Children’s Hospital, who was not involved in the study, called the report interesting and timely. She cautioned, however, that the study was limited by relying on patients' memories from decades earlier, not including elementary school-age children and only looking at Europeans.

As for the danger from skin cancer, "I would recommend that parents still encourage their children to spend more time outdoors, but of course protect them in the usual manner with hats, sunglasses and sunscreen," Yen said.