Speaker 1: Welcome to brain stuff from how Stuff Works. Hey, brain stuff,
Speaker 1: Lauren vogelbamb here there's a myopia epidemic going on. In
Speaker 1: n seventy two, about of Americans aged twelve to fifty
Speaker 1: four were diagnosed with this condition, which is also called
Speaker 1: near sightedness. But today some forty of young Americans are
Speaker 1: receiving the same diagnosis. And that's nothing compared to Asian countries,
Speaker 1: where of high school kids are now near sighted. In seal,
Speaker 1: ninety six point five percent of nineteen year old males
Speaker 1: are myopic, and researchers say that by the year twenty
Speaker 1: fifty five billion people will be wearing glasses to combat
Speaker 1: near sightedness. That's more than half the people in the world.
Speaker 1: How did this happen so fast and so many people.
Speaker 1: While intuitively you might think it has something to do
Speaker 1: with all the time we spend staring at computer or
Speaker 1: smartphone screens, it's not so cut and dried. The rise
Speaker 1: and near sightedness started happening before the prevalence of those
Speaker 1: screens and has been studied at least since the nineteen sixties.
Speaker 1: The latest research reveals that the world's rising myopia rates
Speaker 1: stem from spending too much time indoors in general, Several
Speaker 1: studies show the less time children spend outdoors, the more
Speaker 1: likely they are to develop myopia. This could explain the
Speaker 1: much higher myopia rates in Asian countries, where a stronger
Speaker 1: focus on education keeps kids indoors for more hours than
Speaker 1: children living in most other parts of the world. We
Speaker 1: spoke with Dr Adam Clarin, a Florida optometrist. He said
Speaker 1: the progression of the number of myopic patients has risen
Speaker 1: too fast to be explained by genetics alone. Unfortunately, the
Speaker 1: data is not conclusive enough to determine what parts of
Speaker 1: being outside is protective against myopia. Is that the sunlight,
Speaker 1: is it looking at distant objects, or is it something
Speaker 1: we're not even thinking about. Near sightedness is caused by
Speaker 1: an elongated eyeball. Normally, the light that flows into your
Speaker 1: eyes focused directly on the surface of the retina, but
Speaker 1: if your eyeball is a bit too stretched out, the
Speaker 1: lens will focus the lights slightly in front of the
Speaker 1: retina instead, resulting in blurry vision. The hypothesis about myopia
Speaker 1: that's gaining the most traction says that when the neurotransmitter
Speaker 1: dopamine is released into the retina. It prevents your eyeball
Speaker 1: from elongating and blurring your vision, and light is what
Speaker 1: stimulates this release of dopamine. Normally, a pair of glasses
Speaker 1: or contact lenses is all that's needed too sharpen your vision. However,
Speaker 1: of those with the condition have a heightened form called
Speaker 1: high myopia. People with high myopia are at a risk
Speaker 1: for developing cataracts, glaucoma, torn or detached retinas, and even blindness.
Speaker 1: Although no one knows how much time spent outdoors is
Speaker 1: enough to forestall myopia, one researcher at the Australian National
Speaker 1: University in Canberra estimated the amount at three or more
Speaker 1: hours per day. It's also possible that strong indoor lights
Speaker 1: could help, but Dr roheat Varma, director of the University
Speaker 1: of Southern California I Institute, told us via email that
Speaker 1: even if the myopia boom is not directly related to
Speaker 1: children spending more time indoors looking at a screen quote,
Speaker 1: these are two sides of the same coin. Spending more
Speaker 1: time indoors equates to spending less time outdoors, especially during
Speaker 1: the day. Researchers are still trying to determine the real
Speaker 1: fix for the myopia epidemic. Dr Claarin said other studies
Speaker 1: have shown that a low dose of atropine eye drops
Speaker 1: can also slow the progression of myopia. These studies are
Speaker 1: completely unrelated to the studies on being outdoors, so there's
Speaker 1: obviously more than one mechanism at play. Hopefully, continuing research
Speaker 1: will shed some light on this growing problem. Today's episode
Speaker 1: was written by Bellinie redz Kien McManus and produced by
Speaker 1: Tyler Clang. For more on this and lots of Far
Speaker 1: Side of topics, visit our home planet, how Stuff works
Speaker 1: dot com.