Why can’t we see very well? Reading under the covers certainly didn't help.
I’ve had glasses since I was 8. I can’t remember the last time that I woke up in the morning without reaching toward the bedside table in order to bring the blurry world into focus. I’ve had contacts since I was 11, and I wear them most days: plenty of friends have no idea just how myopic I am. (Very.) And I’m always surprised to find out that this friend or that friend has bad vision. We all seem to have bad vision.
Why can’t we see? I’ve always assumed that, in my case, it’s because my parents both have bad eyes. But according to a new paper in The Lancet, genetic factors can’t explain why increasing numbers of people need glasses. Studies in places like Singapore of people of a variety of backgrounds—Chinese, Malay, India, in this case—show that genetic heritage doesn’t impact rates of near-sightedness. It’s impossible to explain the boom in bad eyes without looking at how people spend their time.
Most of my friends have spent many years in school, which is good indication that their eyes have betrayed them. In the Lancet study, a team of ophthalmologists writes about the rise of myopia in East Asia of the past few decades. In cities in China, Japan, South Korea, and Singapore, 80 to 90 percent of people finishing high school are nearsighted, they report. The study reports that “children who read continuously or at a close distance” were more likely to have bad eyes. But it’s not entirely clear that the “near work”—hunching over a desk, reading books with tiny print and writing long essays—contributes to near-sightedness, though. (The study calls the support this connection “not strong.”)
What is clear, though, is that kids should be giving in to a classic parental dictum: Go play outside. More time spent outside protects against near-sightedness, according to the study. One comparative study that the authors cite found that “time spent outdoors” was the only factor that distinguished kids of Chinese heritage in Singapore, who had high rates of myopia, from kids of Chinese heritage in Sydney, who didn’t.
It might be the bright light. It might be the chance to look at objects further away than a computer screen. But going outside helps. That doesn’t have to mean playing sports. It can just mean being outside.
In America, at least, kids are doing the opposite. They spent eight hours a day looking at TV and computer and video game screens. Recess is getting cut. Having to get glasses isn’t the worse fate that can befall a person. But there’s a slew of other reasons why kids should be going outside. Crisp, clear vision isn't the only benefit.