It seems like every other week there's a study about how smartphones are negatively impacting our mental capacity or sleep cycles. And now there's a study that suggests an overwhelming amount of young people will have to look forward to a life of bad eyesight.
You'd think this would be from staring at our phone screens all their lives, but smartphones aren't the villain for once! Scientists now believe a significant global rise in nearsightedness is happening because kids don't go outside enough.
Science journal Nature reports that the world's growing levels of nearsightedness are approaching epidemic levels. Some 90% of teenagers in China are nearsighted, compared to 10-20% six decades ago. Worldwide, roughly 2.5 billion people are expected to develop myopia (the technical term) by 2020.
After weeding out other factors like too much reading or time spent on a computer, researchers hypothesized that it actually came down to kids' eyes not being exposed to enough natural light.
A nearsighted eye is elongated, so the light focuses before it hits the back of the retina. It turns out that bright, natural light affects the eye's growth, preventing the elongation of the eye during its development. Esquire adds that myopia can lead to cataracts, glaucoma and blindness.
One researcher estimates that if kids were to spend three hours per day exposed to bright sunlight, they could prevent the onset of myopia. Just how bright? 10,000 lux, which is apparently equivalent to wearing sunglasses in the shade on a clear summer day. For comparison, a well-lit classroom is about 500 lux, according to Nature.
In line with this natural light theory, only 30% of 17-year-olds are myopic in Australia, where spending time outdoors is the norm, compared to the one or two hours on average that youths in America, Europe and East Asia spend outside, where the myopia rates are much higher. It might be time for us to step out of the shadows and stop living like vampires.