I always thought it was because all of the "far away" stuff is outside and a person who spends 90% of their time indoors never has to look at anything far away.
What are the rates of shortsightedness among people living in dense forests (or some other cramped outdoor environment)?
> In the early 2000s, when researchers started to look at specific behaviours, such as books read per week or hours spent reading or using a computer, none seemed to be a major contributor to myopia risk.
How would you study those two potential variables seperately to find the true cause?
It would be difficult to have such a large indoor area that people regularly focus far away. But maybe you could keep UV lights on indoors in an animal study to see if the UV light reduces myopia.
Nearsightedness seldom means you can see all nearby stuff. For me, even a notebook kept on my desk is too "far". I don't think living in a dense forest would change anything. I don't think growing nearsightedness is because we are "evolving" to our surroundings.
I know you are being facetious but it's probably important to note that the LED and oLED light used in phones is not wide spectrum.
I think attempting to generate the equivalent intensity of natural light means unnaturally high intensity three component narrow band frequency exposure?... I can imagine that might pose a non obvious risk to eyes because it _looks_ visibly equivalent.
(sorry I am unable to reference it but there was some research into the negative effects of this recently given the advent of LED lights replacing incandescents)
Note: the top rated post has focused on editorial quality and glossed over the fact that it is narrow band light and cannot be compared as equivalently in wide spectrum terms beyond perception (e.g colour temperature), this is pointed out in the 2nd immediate child by sandworm101.
I should point out that the properties of the light beyond perception _are_ important due to ipRGCs: the mammalian retina contains ipRGC photo-receptors that do not relay images to the brain but are responsible for various reflexive responses. These receptors are sensitive to a wide spectrum of light peeking around blue [1]. Ultimately these ipRGCs release melanopsin which is known to affect circadian rhythm, and is thought to control sleep wake patterns [2].
I expect you've heard about this vaugley before as I have, but what is interesting in the context of LEDs is that ipRGCs appear to respond to more of a continuum of spectrum, so unlike our cones they would be "perceiving" LED light quite differently to our consciously perceived images.
I can only imagine the problem getting much worse in the future. Wherever I go, I see kids of all ages hooked on cell-phones - either on mobile games, youtube videos or on instagram/snapchat. This is probably significantly cutting down their natural light exposure.
Why would cell phone use cut down on natural light exposure compared to books or TV? The whole point of a cell phone is that you can use it anywhere, including outside. Based on the thesis of this article, all you need to do is play on your cell phone while you're outside to prevent myopia.
I use my cell phone a lot more indoors than outdoors. I don't go outdoors because my cell phone enables me to connect with people indoors when I would normally be required to go outdoors to connect with them without a cell phone.
When I was a young child I was on my computer or playing video games on a TV all day, rarely going outdoors. When I got my first smartphone, it was actually very liberating. Now I could be outside anywhere, and still surf the internet and play any number of games at any time.
Afaik that's a very generational thing, people a bit older than you spend a whole lot more time outside.
My first smartphone (the first iPhone one) gave me the same liberating feeling you describe there, but it didn't take long for me to realize that mobile gaming isn't for me and while I can do most stuff I want on a smartphone, I can do it better and more efficiently on a full-blown desktop/laptop with proper peripherals, so that's where I still end up doing most of it.
In recent years my smartphone even feels more of an annoying hassle than an actual asset, except for the occasional use for navigation and regular use as mp3 player.
> I would normally be required to go outdoors to connect with them without a cell phone.
Forgive me for being a pedant and a devil's advocate, but would you _really_ otherwise be going outside to spend time with people, and in such a capacity that cell phone use could replace it?
When I think of "spending time outside with people," I think, "afternoon in the park" or "at a restaurant or cafe on a patio" or "hiking." I can't think of any outdoor activities with other people that would otherwise could be supplanted by cell phone use. Playing the Facebook messenger basketball isn't going to replace a walk with a friend.
My understanding is that myopia onset is linked with natural light exposure in preteen-adolescent years. While there is always going to be some segment of people who stay in (who are likely overrepresented on HN) there would have been plenty of children playing sports or playing in dirt who nowadays are on their mobiles, probably indoors because the sun glares the screen.
Screens have glare. When I read a book I want basically all the light I can get, eg. being outside is fine. When I'm on a screen, it needs to be dim around me so I can see.
I've had several optometrists suggest to me, based mostly on anectodal evidence, that excessive use of small screens lead to more cases of astigmatism than simply myopia, which is even harder to correct.
This is an interesting article, but I found I was able to read it, for the most part, by reading the first sentence of every paragraph. That shows how much fat there is in the typical magazine article.
This is actually something many authors aim for. Few readers need all the details, but some do, and this makes it obvious where to dig. It’s harder than it looks to pull off, without sounding stilted... perhaps because it’s the opposite of storytelling, where you build up to a punchline.
Any article about myopia which doesn't mention anything about nutrition is "shortsighted" (pun intended).
One of the most interesting discussions around causes for myopia is centered on nutrition, and how growing faster than our ancestors can negatively effect our vision.
I looked for a specific reference to share here (something I've read years ago), but I didn't find it.
> One of the most interesting discussions around causes for myopia is centered on nutrition
Did you read the article? It asserts that the change in percentage of people who need glasses is startlingly fast. Much too fast to be explained by nutrition changes. It is time spent outdoors.
That's because what you eat has nothing to do with the shape of your eyeball, and there's no scientific basis for bringing this up in the context of myopia
Cow growth hormone does not work on humans. And even if it did, it gets destroyed by acid in the stomach. That’s why bodybuilders inject HGH instead of taking it orally.
After reading this article, I think it's borderline cruelty to give adolescents detention during recess for misbehavior. If anything, this enables more pent up behaviors which could lead to myopia.
TL;DR "After studying more than 4,000 children at Sydney primary and secondary schools for three years, they found that children who spent less time outside were at greater risk of developing myopia."
There was a thread on here recently about the Trades Industry, and many people warned that even though you are up and using your body, not looking at a screen 8hours a day, there are still back injuries etc related to that mobile profession.
I suppose though on average non-sedentary jobs with minimal indoor computer screen jobs have a lower rate of myopia increase..
Is it worth the pay raise to work in tech if our eyes , one of the most imporant senses is put at a higher risk? What about the whole population of young up and comers.
I think e-ink screens will help in 3-4 years when refresh rate is high enough. More people can work on screens in direct sunlight.
She was well educated in France with a liberal arts degree, married well and never had to work, went mountaineering with her husband on holidays, hosted German soliders during the second world war but didn't mind it very much, spent her mornings in prayer, had an elaborate skincare routine, smoked, drank, ate lots of chocolate and rode her bicycle every day right up until the end at age 122.
If sunlight exposure is the cause of too long eyeballs, shouldn't kids which are at hereditary risk of developing too short eyeballs be put in darkrooms?
I don't have any real evidence, but anecdotally I suspect that diet also has an effect on vision. Could be just a coincidence, but my vision declined as a child during a period when I was regularly stuffing myself with sweets, and know others with similar experience.
Is the diet in East Asian countries (Hong Kong, Taiwan, Singapore & South Korea) significantly worse than it was in the 1920s? As the article details, myopia is increasingly common in China as well. The Chinese suffered numerous famines between 1920 and 1960.
I'm sure diet plays some role in eye health, but nutrition has likely improved in all of the countries they're discussing.
Another anecdote: I've consumed on average multiple cans of soda a day since I was in highschool, and while this habit has had a disastrous impact on my health I have always had exceptionally good vision (I can read the bottom line on the eye chart).
try this:
take a picture, same object, no flash, ... one under normal bright sun and another in a room under normal bright lighting. which one is sharper?
set phone brightness to lowest, another on highest. try to read something and measure your arm's length. adjust brightness so you can still focus at farthest arm's length as comfort dictates. don't save on power juice. your eyes are more important.
drive outside and then go to underground parking lot. you'll notice it's harder to look.
use your normal glasses in a normal lighting room. go outside and swith to lower power (say your previous glasses). notice the difference.
the problem was i used the same power glasses all the time, out of habit. the very same glasses for reading far (chalkboards) and for reading books. it's somewhat not practical to switch glasses every time you copy something from board and write to your notes. using lower powered glasses and move my seat to the front mitigate this problem.
tldr; try to get maximum amount of light to your eyes as comfort dictates. if you really have to use glasses, choose the one with lower power that's sufficient for your need. practice to never use glasses for most tasks (adjust brightness on smartphone). you'll be surprised on what ur eyes can do without glasses.
More specifically it's the bright light triggering the iris to close that improves the focus. As the aperture narrows (iris closes) the incoming rays become more collimated (less scattered) and so the image falling on your cornea appears sharper even if your eye's lens is not able to focus it correctly. At it's extreme this effect allows the pinhole camera to work without using any lenses at all to focus the image.
The thing is though, while using lower powered glasses might help you train the muscles around your eyes' lenses to be stronger, mitigating the myopia slightly, the root problem still remains: your eyeball is the wrong shape and there's only so much your eyes' lenses can do to make up for that.
seeing things under sun is not equal to squirting ur eyes to focus the incoming rays
it's just that much light coming, the intensity of light to be exact.
that's why camera, given the same setup, gives sharper image under bright sun light
I never get as tired playing outside as compared to squirting my eyes all the time just to focus in a room. sun light is just that intense, rooms lightings are much less intense.
Cameras only give a sharper picture in bright light because this allows you to reduce the aperture size. The image is not sharper if you increase the shutter speed instead of reducing the aperture. This is basic physics. Bright light is not magical.
Squinting your eyes is a very poor approximation to what your irises are doing. The light collimation is not reduced uniformly in every axis and your eyelashes partially obscure the light.
Now that you can buy good quality glasses online for less than $50 from the same Essilor labs that supply local stores, it is practical to wear situation-specific pairs, especially for computer work.
Sunglasses are something else to consider. There is zero scientific evidence sunglasses protect your vision in any way. (There is suspicion UV exposure can lead to some eye diseases, but it's not a proven link, nor are the mechanisms understood). If increased exposure to sunlight is correlated with better vision, we better revisit our completely non-scientific sunglasses dogma.
Those ailments typically present much later in life. If sunglasses protected against them while making myopia more likely, there would be a trade-off to consider.
This is not scientific in any way. when I'm exposed to sunlight for a long period of time without sunglasses, at night my eyes hurt.
I tend to think that pain is a way the body has to let you know something is not right.
I don't know if photokeratitis of the severity caused by normal outdoor activities has long-term consequences, but more severe UV exposure such as from welding without goggles can definitely cause permanent damage.
What are the rates of shortsightedness among people living in dense forests (or some other cramped outdoor environment)?