Modern Living Is Giving Us Bad Eyesight

Step away from your computer and get outside

Credit: Hans Neleman/Getty Images

ByBy 2030, 40% of the world’s population will be nearsighted, up from 28% in 2010. The number of people with high myopia—severe short-sightedness—is projected to almost double during that time, affecting 516.7 million people. Researchers say increasingly digital, urban lifestyles are to blame for that declining vision, and East Asia, Southeast Asia, and North America will be particularly hard-hit. Already in Taiwan, more than 80% of teenagers have myopia.

The data, which stems from a 2016 Ophthalmology paper, was published in the World Health Organization’s first World Report on Vision this week.

Myopia occurs either when the distance between the cornea — the clear protective covering at the front of the eye — and the retina, which converts light into brain signals, is too far, or the cornea is too curved. That distance or curvature means light rays fall in front of the retina instead of on it, making far-away objects appear blurry.

Myopia develops during childhood while the eyes are still growing. The condition stops progressing when the eyes become fully mature, typically in the early to mid-20s. If vision deteriorates at a faster rate, people can end up with high myopia, meaning sight is 20/400 or worse and requires a prescription of at least -5.00. People with high myopia have a greater risk of developing glaucoma, cataracts, retinal detachment, and macular degeneration, all of which can lead to permanent blindness.

Myopia is partially genetic, so if your parents are nearsighted you probably are too. But environmental factors also influence eyesight, especially when people are young. One of the biggest connections is between education and myopia, with more years of schooling, time spent studying, and even higher academic grades linked to increased myopia. That’s right, the old trope of nerds wearing glasses is actually rooted in truth. Numerous studies have shown that the more time kids spend on “near work,” such as reading, doing homework, using a computer, or playing video games, the greater their likelihood of developing myopia.

“The development of myopia is stimulated by schooling, particularly where competition (homework for example) starts early,” says Ian Morgan, a professor of biomedical science and biochemistry at Australian National University, in an email to Elemental. “This leads to early development of myopia, and since myopia progresses (worsens) during childhood, this naturally leads to high myopia.”

“Your children can become doctors and journalists, whatever they want to be. It’s not going to limit what they can do in life.”

The eyes have to adjust every time they focus on objects close up versus far away. If the eyes are constantly focused on near work while they’re developing, they eventually start to physically change to make that close work easier. The resulting growth lengthens the distance between the cornea and the retina, causing myopia.

“When you’re holding something really close, your eye accommodates. It kind of squeezes itself so that you can read that image,” explains Meraf Wolle, an assistant professor of ophthalmology at Johns Hopkins University. “That gives a stimulus to your brain for your eye to grow because you shouldn’t need to accommodate that much, and making your eye longer means you’re going to be more nearsighted.”

One way to try to offset this effect is to make sure kids take breaks every few hours from reading or computer games. Just as important is not sitting too close to the TV or holding a book or iPad directly in front of your face.

People who live in cities also tend to have worse eyesight, potentially because of less natural light in apartments and the increased density of tall buildings blocking out the sun. Children in urban areas spend less time outside than their rural counterparts, too.

The good news is that more time outdoors — ideally at least an hour a day, particularly in the afternoon when the sun is strongest — can offset the risk for myopia. The theory is that sunlight boosts levels of the neurochemical dopamine in the brain, and dopamine stops the eyes from growing. In China and Taiwan, two areas where myopia rates are rising the fastest, prevention programs are being put into place, increasing children’s time outside to offset the many hours they spend studying.

“Time outdoors [is] the most important environmental factor identified to date that affects the growth of the eye and the development of myopia,” writes Ohio State University optometry professor Donald Mutti in an email. “As populations develop economically and educationally, they will spend more time indoors and be more likely to develop myopia.”

While most people can correct their short-sightedness with some chic Warby Parker specs, not everyone has access to prescription glasses. Globally, eyeglasses coverage ranges from 2% to 93% of the population, depending on the country. According to one study, the global cost of uncorrected myopia due to lost productivity was $244 billion in 2015 alone.

But Wolle says parents shouldn’t panic if their kids are myopic. “The majority of myopia, both low myopia and high myopia, is treatable with glasses, contact lenses, laser surgery if needed,” she says. “Your children can become doctors and journalists, whatever they want to be. It’s not going to limit what they can do in life.”

Health and science writer • PhD in 🧠 • Words in Scientific American, STAT, The Atlantic, The Guardian • Award-winning Covid-19 coverage for Elemental

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