How to maintain good vision amidst the myopia epidemic
ssathe.substack.com62 points by plun9 13 hours ago
62 points by plun9 13 hours ago
Article misses the mark a little bit. "Outdoors" preventing myopia isn't about focusing distance, it's about light levels. Dimmer light makes the eye think it isn't done growing, so it grows more.
You can replicate those light levels indoors, if you're bloody minded enough to do so. It's somewhat expensive but for a tech-enabled crowd not too difficult.
You need about 10x to 100x the lighting most people are satisfied with indoors, and you need to turn it on whenever you're in the room and leave it on between sunrise and sunset. This is easiest with timers and automation.
The most important thing about all of this is to realize that children NEED outdoor recess sometime between the hours of 10am and 2pm every day. They don't have to be directly exposed to the sun, but they need to be in an environment with >1000 lux, more is generally better, for a number of hours. This will prevent their growing eyes from continuing to grow indefinitely.
We know this because there was an intervention in Taiwan, which has extremely high myopia levels in children (80%+ last I heard), and it dropped myopia from ~80% to ~35% in the intervention group. That's an astounding effectiveness for something free.
>> Dimmer light makes the eye think it isn't done growing, so it grows more.
Does that mean that populations in places with more sunlight (e.g. close to the equator) have less myopia than populations with less (e.g. close to the arctic)?
I wonder, wouldn't this mean that in nordic countries, where in winter get less than 6 hours of sunlight in total, and where that sunlight is mostly obstructed by heavy clouds, would be the place with most myopia in the world? For example in Latvia where I grew up, winters last from november to march-april, the nights are long, and it can be months without any sunlight. And it gets darker once you go further north - Finland, Norway, Sweden. But back in my preschool, we had 1-4 kids per 30 in the class, with any eye problems. I myself was among those few who had hypermedia, some even got rid of it by age 10-13. And if I look at the my parents, and grandparents - even fewer had need for eye correction.
Genetic adaptation of humans is a thing.
One way to test it out would be the rates of myopia of people from lower latitudes that have migrated to the nordics.
Valid point. I guess then in Canada they could have a lot of such cases, as it has been a major destination for migration. In any case, sounds like an good topic for a research paper
I've read a number of anecdotes about benefits of bright, full-spectrum indoor lighting and I'm increasingly sold on the idea.
The only thing that makes me hesitant is the extreme unpleasantness of direct high brightness artificial light. I wonder if an indirect lighting setup of similar brightness could be as effective.
It is. The best I've seen make use of essentially bright overcast levels of lighting, so more like 2000 lux, and it's extremely pleasant.
This guy has a pretty compelling version:
https://www.youtube.com/watch?v=6bqBsHSwPgw
If you look at his scatter pane, that's where I would go. There are companies that sell similar lights retail, but they're perhaps 3x as expensive.
Interesting, it seems really likely that more light indoors should be good. Do you have a reference, a scientific study on the topic? Thanks!
Here's a couple from a random search for the convenience of the forum:
https://pubmed.ncbi.nlm.nih.gov/29371008/
https://reviewofmm.com/light-as-a-tool-for-myopia-control/
I can't find the site that I read a while ago, it was very similar to the myticker.com site that was posted the other day for heart disease but focused on myopia.
Thanks for sharing this! I've never heard of this research, but it sounds very promising.
I also found this Guardian article from a Google search: https://www.theguardian.com/world/2025/mar/01/shortsighted-t...
It's difficult for artificial light to compete with full-spectrum natural daylight from an infinitely distant light source (sun). See previous attempts at sunlight simulation indoors.
I'm not sure why you're convinced that focusing distance is irrelevant. Everything I've seen indicates that it is the combination of focusing distance and light level.
Also... 100x the lighting indoors strikes me as quite difficult? Do you have any examples of a realistic setup?
Think operating room or photo studio. 100w grow light panel for every 2-3 square meters - so for a typical office, 4 100w lights, with a scatter panel in front.
I really like this video for an example of how to make proper scattering effect, but you can buy similar materials that are more durable and lighter, for in e.g. a drop ceiling:
Because studies that controlled for focus distance (ie compared children reading indoors v children reading outdoors) seemed to show that focus distance did not have an impact.
Solving focus distance is expensive. If you could prevent this with something cheap, why not ?
I have fairly bad myopia (-6) and I was outside a lot as a kid. I don’t buy this argument, at least not universally.
Practically nothing in health science is universal, your anecdote does not disprove anything.
And I had fairly bad myopia before I could read or had ever seen a computer, would you like to reject the argument that reading or screens are relevant as well?
This article is written in a way that will propagate the myth that screens are bad for your eyes. Screens are not uniquely bad. The myopia epidemic is not caused by screens per se, but by a lack of time outdoors during childhood. What is it about time outdoors that prevents myopia? It is some combination of much brighter light, broader light spectrum, and objects in your peripheral vision being farther away. I don't think it is fully known yet which of these factors is most important, and I am skeptical of claims that one in particular is to blame over the others. But ultimately some combination of these factors provides the signal to your retina to stop growing once it reaches the right size, which prevents myopia.
As long as you get a few hours outdoors most days during childhood, it doesn't really matter (from the perspective of myopia prevention) if you spend your indoor time in front of a screen or not. And if you don't get that outdoor time, avoiding screens won't save you from myopia. Screens are not really relevant here except to the extent that they encourage children to spend less time outside. You could just as easily blame HVAC or other conveniences of modern homes that make it nicer to stay inside.
I keep hearing this, but I spent a lot of time outdoors as a child. Hours every day, riding bikes with friends and running around with BB guns in the woods. We played a lot of video games and read books, too, but we spent plenty of time making tree forts and "sword fighting" with old pipes. Still needed glasses by the age of 7.
Obviously, genetics also plays a role in individual cases. We're talking about the population level here, and genetics doesn't explain the myopia epidemic, because population-level genetics hasn't changed rapidly. Time outdoors has.
I believe that more screen and reading time causes more childhood myopia. That seems hard to refute. I just do not believe, without serious peer-reviewed studies, that "a couple hours a day outside" is the magic cure. Out of my friend group, 3/4 of us needed glasses, and we definitely met the "couple hours a day outside" criterion. But we also loved our Street Fighter 2.
Various peer-reviewed studies exist and have been covered by pop science articles over the past 15 years or so.
Here is an example one; there are likely dozens available.
Study with 65 citations: https://pmc.ncbi.nlm.nih.gov/articles/PMC7607527/
Pop science article with more context: https://www.theatlantic.com/health/archive/2014/05/nearsight... (https://archive.is/OeuC3)
Same here. Both parents though wear glasses from young age so I think genetics will always be the main factor.
In my early teens I had 20/15 vision. By my mid teens I was into computers and wearing glasses, despite copious time outdoors.
Just anecdata, perhaps, but same.
I did nerdy kid stuff like read lots of books and use computer screens (uncommon back then, I'm 52)... but I also played outdoors for hours nearly every single day.
Ended up with vision at -6.00 by the time I was a young teenager (don't remember the age it started to slide that way but would estimate around 7-8 or so). Hasn't gotten any worse (or better) since then.
I don't think that's true at all. I had prefect vision up until I graduated college and started spending 10hr a day behind a screen - within two years I ended up getting glasses, although they are a mild prescription and I don't really need them other than driving at night. My friend was in a similar position and they also ended up getting almost the same prescription.
My eye doctor said it was my eyes optimizing for what they do the most. And that makes sense, I have no eye strain using a computer.
Interestingly my vision is better in the summer, and when I take holidays during the summer and spent time away from the computer my eyes essentially fix themselves. It takes a couple months back behind a screen to need my glasses again.
Yes but it's might just be a different mechanism from childhood -> adult myopia. Where you go from perfect vision to -5
Counterpoint: I have spent 10hrs a day in front of screens since I graduated from college and my eyes are fine.
> But ultimately some combination of these factors provides the signal to your retina to stop growing once it reaches the right size, which prevents myopia.
Are you conflating retina with eyeball? In some/many cases, it’s the length of the eyeball being too long for correct focus on the retina. The retina doesn’t keep growing and cause myopia.
It could be both. And focus distance may matter. Like, books may also cause myopia. Reading books outdoors may be a bit better than reading books indoors. Using screens at a distance could also be benign.
Ha! My parents also thought this was the case, I was a child before the internet and phones, my favourite hobby was playing around in the trees next to our soviet commie block.
I had an incredible childhood with building hidden dwellings in the woods, unsupervised fires and bicycle journeys, football, building ice castles etc, swimming and martial arts lessons. My parents even limited my TV time to 2h a day.
But I still had —1 myopia for every grade until 7th.
My analysis is that by that time I got into reading books - both science and fantasy, and then boom my eyesight was fucked.
Thank god for LASIK.
>My analysis is that by that time I got into reading books - both science and fantasy, and then boom my eyesight was fucked.
When I became a heavy reader I speedran long sighted to short sighted. I think 4th grade I got my long sighted diagnosis. 5th grade I started lifting heavier books. By the end of 7th I had more or less the prescription for Myopia I have now.
> In my opinion, it’s too early, too ambiguous, and the jury is out on whether myopia can actually be reversed.
We do need studies on if/why/how myopia reduction works for some people.
However, we already know a guaranteed way to increase myopia:
1. Wear corrective lens for 20/20 vision for distant objects, e.g. driver license vision test.
2. Keep wearing distance lens for closeup, e.g. phone at 12".
3. Keep wearing distance lens for near work, e.g. book or laptop at 24".
4. Keep wearing distance lens for intermediate, e.g. monitor at 36".
5. Eye adapts (more myopia) to get 20/20 vision at daily focusing distance, e.g. work laptop.
6. Optometrist measures that distance correction with lens is now worse than 20/20.
7. Optometrist increases distance correction to get back to 20/20, for legal (e.g. driving) compliance.
8. Go to Step 1.
This is also what I came up with, with my own experience. Basically, everytime I get prescription glasses for myopia, my myopia gets worse a few months later. What baffles me is that none of the professional I've seen (I think 2 ophtalmologists, 1 orthoptist, 1 optician) told me about that Now I feel truly bitter about the eyes professionals, even though I'm sure they are good at catching defunct eyes, I feel like they don't know how what to advise you, when it gets worse and worse.
Another nuance is that vision decreases during the day, so you want to avoid an eye exam late in the day when vision is weak, resulting in a stronger prescription.
Low ambient lighting and dark mode for work will increase pupil dilation and reduce focus. Better to match monitor brightness with natural ambient light levels.
Vision therapists are better at personalized treatment, https://locate.covd.org
It's worth trying to reduce myopia, if only to reduce the thickness/weight of glasses, https://hn.algolia.com/?query=walterbell%20myopia&sort=byDat...
I noticed this yes. I even had a eye exam with some eye drop that makes your muscle sore, so you can't focus closely anymore, but the doctor is 100% sure that muscles are not focusing passively
I have eye glasses, but I do not use it when I am working on computer, nor when I am reading or writing a book or paper. I only wear it when I need to see things far away. (I also do not have (and do not intend to have) a driving license.)
How does one "buy dedicated lenses for that distance"? The distance between my eyeballs and my screen is 28 inches, but I do not know how to translate this into what to buy.
Ask optometrist for "intermediate lens" prescription for the distance of your screen.
Ask optician to customize the intermediate/computer glasses for your work posture, e.g. looking straight ahead (monitor) or down (laptop).
For those with more time than money, learn from opticians at https://www.optiboard.com/forums/ before ordering online.
"Cheaters": Get the lowest power reading glasses they sell at the drug store.
You can also order 0.75 diopter glasses on Amazon that work real well.
The formula is:
your prescription - (100 / desired distance in cm).
As a matter of fact I'm using glasses I bought this way right now. I actually find these even more comfortable than my full degree glasses for all-day use too, in terms of eye strain.
I feel it's ridiculous that the medical industry thinks I need to wear glasses that are powerful enough to focus an image of a mountain 100 kms away all day, when my average focus distance throughout the day is probably less than one meter.
These reduced degree glasses are called differentials. If you want to go into the rabbit hole of fixing your myopia, start here: https://www.youtube.com/watch?v=XPIGDSY_xBs
Disclaimer: When driving, you have to obviously wear your full prescription glasses.
I don't currently have any known vision problem nor wear glasses, I was only looking to reduce eye strain since I regularly need to take breaks due to my eyes hurting after using the computer for too long. I have had recent eye exams and they were 20/20.
That being said I'm even less sure how to calculate it now.
Hmm. I am 67 and require no corrective lenses. Two years ago, at my last exam, the doctor said I was “the one percent of the one percent of people” my age that do not require glasses. All of my siblings and both of my parents wore glasses.
Most of my professional life has been spent staring at screens, usually in darkened rooms, so I have no idea why my sight is still good.
I've worn glasses since I was 6. At least 3 times my glasses have saved me from eye injury.
Us four eyes are wearing safety goggles all the time. I would probably prefer perfect vision instead but blindness avoided is a blessing.
I am not unhappy with wearing glasses all the time. Sure it meant I stink at baseball, tennis, etc., as the ball trajectory is warped by my lenses, but I don't care about that.
Hmm, I wore strong corrective glasses full time as a kid and was good at ball sports. Same for my siblings.
Interesting that you didn't get age related presbyopia and needed reading glasses as a result.
It's one of the more annoying things about getting older, if you didn't need glasses before sometime in your 40's.
Left to their own devices (i.e. without external lens adjustments), one aging eye can specialize in closeup and the other in distance. This will lead to monocular vision that is functional for both distance and closeup. This separation can be assisted by corrective lens.
Vision therapy: https://raygottlieb.com/presbyopia
Expensive progressive glasses have neurological impact, not just optical. Better to use separate distance and reading glasses which manipulate only optics, and provide the brain with a physical signal of "mode" change.
I don’t need or use reading glasses. I have tried some +1.0 readers but they quickly cause me vertigo.
Genetically, I've dealt with myopia on the -2.x range most of my life till I had lasik around 20 years ago. However, now my eyes have diverged in the weirdest of ways. I have 20/20 in my right eye but can't read up close - due to being in my late 40's - and my left eye can read up close but I have around 20/80 for near-sightedness. I guess it's "good" I can handle any situation with one of the eyes but playing pool with depth perception sucks! Anyway, I have a new problem this article never mentioned. Floaters. My left eye is full of them and reading anything with these blobs blocking my vision is a game of moving my eye so it "shakes" things up so I can read where it was blocked. I have not found a therapy for it. Floaters is protein waste broken off in the eye and mine never settle to bottom of the eye. Don't take your vision for granted.
Spending a couple thousand on LASIK was the best investment I’ve ever made. The money I’ve saved on prescription glasses alone has already paid for lot of it, and ten years later my distance vision is still nearly perfect. Now only if there was a similar procedure for my neck and posture..
I just purchased some computer glasses that are optimized for about 38 inches. (A little short of a meter.) I get no eyestrain, and looking far away isn't awful.
I wonder what effects VR and AR will have on this.
Head worn glasses simulate infinity/distance, so they do not impose focus or convergence stress on the eye.
Viture glasses ship with adjustable myopia optical correction to -5.00D (no cylinder), or they have an optional frame for custom prescriptions.
Same. Hopefully AR/VR and other display technologies will mitigate myopia.
Why was this downvoted? VR shows an image at infinity which is much better than other display technologies, and new technologies like micro LED chips can be super bright and even rival the outdoors. Together, both hypotheses regarding myopia are addressed.
> VR shows an image at infinity
Most are in fact measured in feet, and only quite a few at that. Still better than being measured in centimeters however.
Try to experience an hour of 10,000 nits outdoor brightness per day.
Filtering glasses and large screen staying at distance is the answer