screen time

Time spent using a device such as a computer, smartphone, video game console, even television, anything with a screen. It is considered addictive and can lead to a sedentary lifestyle.

Historical perspective: Too much "screen time" and not enough outdoor play may be taking a toll on children’s vision. A 2017 study in India involving school-age kids found that the risk for myopia, or nearsightedness, increased among those who used a device with a screen for four or more hours each week. Rates of myopia—which occurs when the eyeball becomes too long, preventing light from focusing directly on the retina—have doubled in the U.S. and Europe over the past five decades. In parts of Asia, almost 90 percent of 18-year-olds now have the condition, which makes distant objects appear blurry. Researchers believe the main factor is a lack of exposure to direct sunlight, which prevents elongation of the eye during childhood. The issue is not that screens are sending some magic signal to the eye that’s damaging it, ophthalmologist Christopher Starr from New York’s Weill Cornell Medical Center tells CBSNews.com. It’s that when you’re on those devices you tend to be inside and not outdoors in the sunlight.