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Sarah Zhang has pretty much been wearing glasses her entire life. My eyesight is quite bad, and it's actually something that caused my parents and then sort of me a lot of anxiety when I was younger. So much that her parents actually tried to fix her eyes. When I was growing up, my mom would make me do these eye exercises where you kind of like rub your temples or your brows and like move your eyes around. But there's research now to say that these exercises do not work.
But Sarah isn't too worried about wearing glasses these days, especially because almost everyone she knows wears them too. When I see someone who's not wearing glasses, I assume they're wearing contacts now, and I'm almost always right. She started wondering, is this normal? Is it weird that everyone she knows has bad eyesight? When I talk to eye doctors and ask them about this, they're like, oh yeah, it's going up. We're seeing so many more kids. We're seeing kids coming in younger. So Sarah started digging into the research, talking to scientists, and she was like,
And she wrote up what she found in a piece for The Atlantic. Turns out her hunch that more people's eyesight is getting worse, it's true. In the past, like, you know, 70 years or so, people have been noticing that there's been an uptick in myopia. Myopia is just another word for nearsightedness, when you can't see things that clearly if they're far away. And more and more people are becoming myopic.
It's happened kind of most dramatically in Asia, where almost 90% of teenagers need glasses. So that's like nearly almost everyone, right? But it's not just Asia. Eyesight's getting worse all over the world, including in the U.S. The sort of most recent numbers are from the 2000s, which is about 42% of adults are nearsighted. And that's from a quarter of the 1970s. This isn't just making it harder to see.
Myopia can come with long-term risks. In 50 or 60 years from now, you might have people who were myopic all their lives, and now they're kind of developing these really serious eye conditions that can actually lead to blindness. A hundred years ago, this kind of thing was really rare. So what changed? Why is all this myopia happening now?
Something about the way we are living our modern lives, we think that is causing the myopia that we are now seeing everywhere. We are doing something to our eyes that is bad, but we can't pinpoint exactly what it is. I'm Noam Hassenfeld, and this week on Unexplainable, what's ruining our ability to see? And is there anything we can do about it?
So, Sarah, before we get to some of the changes of what's happening here,
What makes someone nearsighted or farsighted to begin with? Like, how does that work in the eye? So an eyeball is usually kind of a round shape. When you're farsighted, your eyeball is too short. When you're nearsighted, your eyeball is a little bit too long. So it's kind of more shaped like an olive. And the back of that eye can get quite thin if you think about taking a balloon and kind of stretching it or squashing it. Like, that's kind of what's happening to an eyeball when it's not the right shape.
And what's interesting is that we are actually all born farsighted as babies. We're not born with perfect vision. Babies are all farsighted. Their eyeballs are a little bit too short. And over the course of our lives, as our eye gets these signals from the environment, it grows the right length so that we have perfectly clear vision. But our eyeballs are just growing a little bit too long.
Isn't myopia something you either have or don't have? Like, both my parents are nearsighted. My brothers and I are nearsighted. Like, is this theory contentious at all that myopia is going up? So originally, if you even go back like 30 years, it actually was pretty contentious.
Some scientists or doctors were actually pretty down on the idea that myopia could be going up so fast because traditionally what we learned is that myopia is inherited. So if you have parents who are nearsighted, you're more likely to be nearsighted. If you have siblings that are nearsighted, you're more likely to be nearsighted. But the idea is that it's genetic. So in that case, the rate of myopia should pretty much
B level across time, right? But now we're seeing this increase, not just in Asia, but also through a lot of the developed world. And I think it's just like, it's so big that it's like, clearly it's not genetics, right? Like so many more kids are myopic than when compared to their parents and when compared to their grandparents. This is like not a matter of genetics. So now it's no longer controversial that this is happening, but why it's happening is still controversial.
What are some theories? Well, there's like a really intuitive theory, right? Which is that like, hey, we're just staring at our phones and our screens and our TVs all the time. Obviously, that's what's going on.
And even like a hundred years ago, before we had electronics, you had people saying, hey, it's like all these people spending time on their books all the time, you know. But it's only become sort of so ubiquitous in sort of the past several decades. I read studies from, I think, the 1960s, 1970s of eye doctors going up to Alaska, as far north in Alaska as you can go, in this really remote areas where they found that there had been this huge uptick in
Wow.
And in Orthodox Jewish communities, there's actually a really high level of nearsightedness, but only among the boys, not among the girls. And that's because the boys are the ones who are spending a lot of time doing their studies and, you know, reading their books. So there's like a pretty
clear, like, environmental cause here, right? And to kind of traffic and broad high school stereotypes, all the nerds are wearing glasses. The jocks are not. I actually grew up Orthodox Jewish, and I spent a year in a seminary in Jerusalem and was studying a lot of Talmud very close to my face, and my eyes got really bad. Oh, well, there we go. You proved it. Anecdotal, yeah. Were your classmates, were they wearing glasses? Everyone's got glasses. Yeah.
So just so I can understand the mechanics here, is the idea that if we are focusing on a lot of stuff near to our eyes, our eyes are...
becoming attuned to only that space? Yes, exactly. So it's a little bit like if you don't use it, you lose it. Basically, by looking at things in front of your face all the time, you're telling your eye, oh, only the things right in front of me are important to focus on. These things are far away. It doesn't really matter. And so then maybe, you know, under this theory, like your eye then grows to say like, okay, I'm only going to focus on things that are near to me. The problem with this theory, which like feels very obvious and very intuitive, is that if you...
go out and do the research and you kind of like track the number of hours kids are spending on what researchers call near work, which is like, you know, reading on your phone, anything that's kind of close to you. If you look at the number of hours kids are spending on near work, there actually isn't much of a correlation between that and how bad their eyesight is in terms of distance vision, which is very puzzling. You know, sometimes a study will find a correlation, but then like another study will not.
So if it's not spending time reading on our phones, what else could be going on here? Well, one more theory is that like, actually, we are going about this backwards. It's not the amount of time you spend looking at things close to you indoors. It's the amount of time you are not spending outdoors that is the problem.
And we don't know exactly why, but there are a couple of theories that have been floated. One is that simply it's a lot brighter outside. And something about that really bright sunlight gives signals to the eyes that are protective in the way that being indoors is not. And just by example, you know, like lux is usually like how we measure how bright, you know, light is. That's like LUX? Yes, LUX.
And so indoors, it might be like a thousand lux. Outdoors on a sunny day, a hundred thousand x. Even a snowy day, 20,000 lux. So this is like a really huge difference in how bright it is indoors and outdoors. And so there's some scientists think it's because there's something in that sunlight that is protective. Because again, we're used to being outside in the sunlight. Makes sense. Another theory holds is that it's not
really about how bright it is. It's really about the fact that when you're outdoors, you're looking at things far away, as we were talking about earlier. Right. That seems also intuitive. Yeah. So we don't, you know, there's no agreement on exactly which part of being outdoors is protective, but there are many who argue that it's not about the fact that you're spending too much time on your work. It's the fact that you're, when you're doing your work, you're not going outside and being exposed to whatever protective effects there are. So
Is there evidence on either? How do we evaluate these hypotheses? I think the question of like, is it the brightness or is it something else going outdoors? I think that's pretty hard to disentangle because, you know, you generally have both when you're outdoors.
I remember having one conversation with a scientist and I just kept asking her questions about like, why are people myopic? How does the eye work? And then she was like, okay, here's another controversial point. And then she was like, no, this part is also controversial. She said this like probably like five or six times over the course of our conversation. I was like, I thought I was just asking very basic questions about how the eye works. Like, why is everything so up for controversy? But I think that
is just that like, you know, it's pretty hard to answer questions in science sometimes. I think what's also difficult is that a lot of the experiments to kind of understand how the eye grows, they have been done in lab animals and like under very specific lab conditions. So often chicks, sometimes monkeys, sometimes rat shrews. And then you can go and like dissect the eye. You can go in and like
do like very controlled things that you never do in a human, like put a kind of like little glass bubble over one eye and then see how the eye grows. And actually what happens is the eye becomes myopic because it's like not getting the right signals from the environment. So in lab animals, we can do this with kind of like a lot of specificity, but kind of under like really weird artificial conditions. Right. It wouldn't be that much fun. Right. Yeah. And maybe your vision might be semi-permanently messed up. I don't think I would agree to that. Yeah, I'm not agreeing either. Yeah.
So I think there's a little bit of a gap between what we can observe in animal studies and what we can then extrapolate to is happening in human eyes. So ultimately, if we don't know the exact cause here, is there anything we can do? Can we stop this at all? So I don't know that there's a very clear answer to exactly what is going on, but we also don't need a very clear answer to try to do something about it.
So I think, like, regardless of what the sort of exact biophysical cause is, like, we know we should probably be spending a little bit less time on our phones and a little bit more outdoors. On the other hand, there are these, like, new crop of treatments that are supposed to slow myopia. And understanding, like, what is going on with myopic eyes can help us understand why those treatments seem to work and maybe try to develop better ones. What we might be able to do about the rise of bad eyes after the break.
This episode is brought to you by Shopify. Whether you're selling a little or a lot, Shopify helps you do your thing, however you cha-ching. From the launch your online shop stage, all the way to the we just hit a million orders stage. No matter what stage you're in, Shopify's there to help you grow. Sign up for a $1 per month trial period at shopify.com slash special offer, all lowercase. That's shopify.com slash special offer.
So over the last few decades, people's eyesight has been getting worse. It might be because of staring at screens. It might be because we're not spending that much time outdoors. Scientists aren't sure. But the question is, what can we do about it? The most obvious thing might just be getting glasses or LASIK, like laser eye surgery, and
But Sarah says these interventions don't actually fix myopia. The thing is, is that LASIK and glasses and contacts, they don't correct what is the underlying anatomical problem of myopia. The problem with myopia is not just that you can't see that well, it's that your eyeball is the wrong shape. So LASIK,
doesn't really change the shape of your eyeball. What it does is it kind of changes like the little clear part in front of your eye, the cornea. It kind of changes that shape of that little clear part in front, but doesn't change the length of your eyeball. So you can get LASA, you can see well, but like all those high risks of things like a coma or retinal detachment, those still apply because your eyeball is still too long.
So once the eye does stretch, whether it's from, you know, looking at screens or doing math problems or not going outside, is this something we can undo? No, we can't. Once the eye gets too long, you cannot reverse it. So this is why eye doctors now are kind of really interested in these new treatments that are called myopia control or sometimes called myopia management. So they can't reverse what's already happened. But what they usually can do is they can make it go a bit slower.
So how do these treatments work exactly? So there's three different types of myopia control, basically. It's an eyedrop or special contact lenses or another set of special contact lenses called ortho-K. So the eyedrops are a chemical called atropine. They've actually been used a lot in eye medicine in the past to dilate your eyes at higher doses to kind of make your pupils look bigger at
At really, really low doses, like at like one one-hundredth of what a typical dose would be, using these atropine eye drops seems to slow the progression of myopia in kids. And
really clear exactly what is going on, but the theory is that it somehow interferes with like the chemical signals in the eye and it's preventing the eye from growing too long. So that's the eye drops that are kind of slowing the progression of myopia? Yeah, you know, it's like the difference between being like nearly blind to like being able to sort of see without your glasses. The contact lenses kind of are about similarly effective and there are two different kinds.
One is called OrthoCarotology or OrthoK. And again, this is an existing treatment that's already on the market, has been used for years and years and years. And what these are, these are hard contact lenses that you wear at night. And it kind of reshapes the cornea of your eyes, sort of like the clear outer part of your eye, so that you can have perfect vision during the day. So you don't have to wear anything during the day, which like athletes really like to do. Wow.
That's like a retainer for your eyes or something. Yeah, but it only sort of lasts about eight hours during the day, so you have to do this every day. Otherwise, your eyes will go back to normal. This is like a very temporary thing, unfortunately. It's not a permanent fix. You have to do it every day. And the others...
the third treatment are soft contact lenses, but they're multifocal contact lenses. And so what they do and actually what OrthoK does is that they change the way that light enters your eye for your peripheral vision, right? So your central vision is what you use to read. It's what you use to concentrate on, what you focus on. And you need that to be very clear. And so it kind of gives you a prescription that you can seek
clearly when you're looking at things at the center. But then it kind of changes the way light enters your peripheral eye. A lot of researchers suggest that it's your peripheral vision that seems to really impact whether you become myopic or not. And sort of like changing your peripheral vision seems to be the key to slowing myopia's progression. So it
These contact lenses sort of do this interesting thing is where they give you clear eyesight to kind of correct your myopia right now, but then also change your peripheral vision to sort of prevent your myopia from getting worse. Okay. So how common are these treatments? I mean, are they accessible? They are.
really common among certain communities and now becoming more mainstream. So it's actually really common among certain Asian-American communities. There's a big clinic up in Berkeley, California, where there are obviously a lot of Asian-Americans
And that's because of the really high rates of myopia in Asia itself. So actually, a lot of these treatments, the original studies that were done, they were actually done in Singapore or Taiwan. So a lot of the studies, the research itself is coming out of Asia, right? So these treatments are sort of, they're building on things that have existed before, but a lot of the research have proved that they're effective in kids.
It's all coming out of Asia. So that's just sort of like the hotspot, the locus where this all originated. So just in terms of it diffusing over here, it's just taking a little bit longer to get to the U.S.
I guess I'm wondering if scientists were able to figure out the precise cause here, would that help things? Would that, you know, enable us to act differently or focus our interventions in the right way? Yeah, I've also thought about this. Like, if we knew exactly what was going on, could we, you know, get more buy-in with like real behavioral interventions? Or would we just end up with sort of like maybe more effective and more targeted, I guess, pharmaceutical interventions?
It's kind of funny. It's sort of the same way like with obesity, you know, the sort of like root society-wide cause is that our lifestyles are more sedentary and we sort of eat a lot more high-calorie foods than we used to. And a
course the way we go about this are sort of just like we buy pelotons and we like take diet drugs right instead of like sort of really changing our lifestyles because that would be so hard like we don't want to go back to a stone age lifestyle like we still want our modern lifestyles so we've like put this layer of technology on to kind of allow us to keep living our modern lives
that when you zoom out seems really bizarre. Like, oh, people are putting like chemicals in their eye and they're putting like little pieces of plastic in their eye and they're kind of like changing the shape of their eyeball. Like what? Like that's so bizarre. But like, hey, that's the world we live in. This episode was produced by me, Manning Nguyen.
There was editing from Brian Resnick, sound design and mixing from Christian Ayala, music from Noam Hassenfeld, fact-checking from Serena Solon, and tons of help from Meredith Hodnot, who manages our team. Bird Pinkerton asked the octopus what was going on. The octopus whispered, her voice shaking. It's the birds. I never thought they'd find us.
Also, special thanks to Maria Liu. If you have any thoughts about this episode or ideas for the show, please email us. We're at unexplainable at vox.com. This podcast and all of Vox is free, in part because of gifts from our readers. You can go to vox.com slash give to give today. Unexplainable is part of the Vox Media Podcast Network. We're off next week, but we'll be back in your feed on September 13th. Bye.
