Nearsightedness, known as myopia, is up 66% in Americans since the early 1970s. And while our increasingly intimate relationship with screens is a potential factor, recent research suggests that a byproduct of excessive screen time — more time spent indoors, and less time soaking in sunlight — may be linked to our worsening eye health, according to a recent study in JAMA Ophthalmology.

Researchers in the U.K. gave more than 3,100 people older than 65 eye exams, and collected information about their lifestyle; specifically, the amount of time they’ve spent outside throughout their lives. People who got the most sun as teenagers (between ages 14–19) were about 25% less likely to be nearsighted by middle age. Researchers also found a “protective benefit” for eyes from exposure to sunlight, especially UVB radiation, up until the age of 30.

“There is something in modern-day childhood that is triggering a massive rise in the number of people with myopia,” Katie Williams, the study’s author, told the New York Times. “And a lack of time outdoors certainly appears to be contributing.”

Read more on the New York Times.

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