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Comment by jdtang13 | Hacker News Reader

The "myopia is purely genetic" zeitgeist has been continually shoved down all of our throats in the west. Meanwhile, studies from Taiwan, Japan, and Korea show that myopia truly has an environmental component to it, e.g. childhood eyestrain and video games. It's also undeniable that myopia manifests more in middle class workers than working class, which indicates some sort of systematic environmental component.

Since the article is specifically about Japan and Asian markets, I must add this: One may argue that the discrepancy in mainstream scientific conclusions could simply be due to differences in genetics between East Asians and Europeans. This mainstream "myopia can't be cured/prevented" rhetoric has been extremely harmful for approximately 2 billion people on this planet.

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The predisposition to myopia is genetic but one becomes myopic due to an environmental factor: the lack of exposure to sunlight. It is because of the lack to regular exposure to sunlight that people who study and spend a lot of time in homes can develop myopia if they are genetically predisposed.

Focusing on nearby objects does not lead to myopia. Doing gymnastics with the eyes has no effect. Likewise, using under-sized glasses has no effect on myopia.

Here a supporting article about Inuit populations developed myopia just in one generation because of changes in lifestyle reducing outdoor activities:

https://www.nature.com/news/the-myopia-boom-1.17120

As a kid, I remember that my myopia disappeared after one summer when I was outdoors a lot. Then it came back soon after returning to school.

I don't think it works like that.

It does seem like a convenient "just-so" anecdote, and I've never experienced or heard of myopia just going away like that, but I also don't think it sounds completely implausible.

I'd imagine it's also less noticeable in scenarios when you don't need to read smaller letters from a distance as much (ie: when you are playing outside rather than sitting in class).

Also in bright light your pupils are constricted so depth of field is greater. In dim light your pupils are dialated and depth of field is shallower. Same principle as a camera lens f-stop.

So the perception that you see more clearly in bright outdoor conditions could be true.

There may be some correlation but there must be other factors. Doesn't fit my history. I'm myopic, -6.0 diopter, needed glasses starting in 2nd grade. Spent a lot of time outdoors as a kid (no computers, 3 channels of TV which was targeted at grownups except for Saturday morning). Being inside was boring.

Nearsightedness also runs in the family on my fathers side, but strangely none of my kids need glasses and they all grew up with much more TV and other screen time than I had.

This reminds me of archetypal idyllic images of ancient Greek education where a philosopher is teaching a group of students in an outdoor amphitheater. Maybe we need to redesign our schools to be outdoor, or at least with indoor structures with generous amounts of natural lighting.

God no, UV radiation is a thing.

And sunscreen is also a thing.

I don’t trust most people to apply sunscreen effectively. You really need a lot of it for adequate protection, and by the time you apply that much, you become an oily slippery mess leaving sunscreen on every surface you touch. It’s easier to just stay the hell away from the sunlight and any surface that reflect light.

Glass also blocks most UV radiation, so lots of windows would be ideal.

That is only possible in a very small climate band.

Maybe just have a ton of natural light in your buildings, energy conservation be dammed?

It's harder now because of screens general inability to work well in daylight, although that might be a plus in most schools.

Outdoor schools were a thing in recent history. It gained a lot of traction about 100 years ago until the 1930's. It was called the "open air school" movement. I think it was started mostly to combat a rise tuberculosis.

https://www.smithsonianmag.com/history/history-outdoor-schoo... https://en.wikipedia.org/wiki/Open_air_school

Daytime sunlight is not the only exposure factor correlated with myopia. Nighttime artificial lighting is also a negative:

https://www.nature.com/articles/20094

There's a review here:

https://www.sciencedirect.com/science/article/pii/S135094621...

I accept that this isn't anything more than anecdote, but my mother was very myopic. I grew up in the boonies, spent loads of time outdoors, had no video games until I was in high school, and was allowed very little TV time.

I still needed glasses by 2nd grade and finally leveled out somewhere around the -8.50 range in my mid-late 30s. Hasn't really gotten too much worse as I got older, but as a lovely side note, I'm in my early 40s now and am getting the slightest bit of trouble on the other end of the spectrum where I can't always focus on small, close-up things if I have my glasses on. Guess it'll be time for bifocals soon.

> "myopia is purely genetic"

I have never heard that Myopia is purely genetic. Where is that claim even coming from?

From tons of articles, medical advices, etc. that insist that "you don't develop myopia from reading, monitor work, video games, etc".

They not not say that it's "purely genetic", but that's the impression one gets, that all those lifestyle params don't play any role...

Wikipedia says it's "a mix of genetic and environmnetal factors", and includes all of the above factors I've mentioned. But I've read many times in the past decades articles insisting that those other things don't matter (and presenting it as the medical consensus)...

> From tons of articles, medical advices, etc. that insist that "you don't develop myopia from reading, monitor work, video games, etc".

As an adult, it would certainly be an outstanding discovery if this did matter. Which is why I'm skeptical about these supposed glasses. Sounds like snake oil, quacks like snake oil.

For children, teenagers and young adults: maybe. It's all about the eye shape, and children's bodies are still in development.

>As an adult, it would certainly be an outstanding discovery if this did matter.

Why not? It's not about being "still in development".

All of our organs (heart, liver, knees, joints, ears) can deteriorate in various ways if we don't take care of them or abuse them in certain ways as adults (e.g. ears and loud music, especially on headphones, can lead to reduced hearing). Heart, well, we can have the heart of a 80 year old at 40 if we have the wrong lifestyle.

So why not eyes as well?

(Not to mention myopia usually rises over time in adults that have it - and they change glass perscriptions etc.), so it's clearly something that develops in adulthood too. Not to mention other things related to the eyes and their plasticity etc., like presbyopia, that strike at ~ 40-45 or so.

> myopia truly has an environmental component to it

Very much possible. I only have anecdotal evidence, but if you plotted the amount of time I spent at home starting at a TV versus other kids, you will probably find interesting correlations.

> , e.g. childhood eyestrain and video games.

Why single out video games in particular? If there is a problem, the problem is the screen. Or rather, how close it is. It is unlikely to be related to the content.

I wouldn't be surprised to learn about a feedback loop getting disrupted. For many organs in the body, an approximate shape will work just fine, who cares if an organ is slightly off by a few millimeters. Not so for the eyes.

The factors weren't "childhood eyestrain and video games". The one consistent factor was the amount of bright light exposure in a study[1]; in other words, being indoors, away from bright sunlight, which is correlative to eyestrain and video games, not causative, because people tend to do those things indoors. If you read outdoors in bright light, it's not really worse than just hanging around in bright light.

Couldn't find a non-paywalled PDF, sorry, but here's the original study:

[1]https://www.thelancet.com/journals/lancet/article/PIIS0140-6...

Also, it might have changed since then (2012). If there's since been a study refuting this one, let me know, because it's nigh-impossible to find between the glut of citation-free news sites and blog posts, and paywalled journals.

The currently favored theory is that it's due to a lack of UV light reaching the eye. It's not (just) video games, it's (also) school and generally being indoors instead of out at midday.

Since I learned that excess UV radiation burns the retina, I've started always wearing sunglasses outside. Should I stop?

The way I understand it is that it only matters while the eye is still developing, so if you're over 10 it's too late anyway. The thing with UV more generally is that we've obviously evolved with them, so while they are dangerous in some respect we also depend on them. In this case, protecting your eyes too much early is probably detrimental, but not protecting them later on probably is as well.

There's no such theory, and exposure to light brightness has nothing to do with myopia. Being outdoors causes less close up focus, which slows the progression of myopia.

Not "light brightness," whatever that's supposed to mean, but UV light.

I have bad myopia (around -5) both my parents have it too and to me it has always been evident that it isn't purely genetic. I think I could willfuly downgrade my vision if I concentrated.

In my family (n=basically_none), it seems that myopia correlates strongly with habits. The most bookish, indoors-y kids ended up in glasses - and the more so, the thicker the glasses - while folks who spent their childhoods running around outside tend to have 20/20 vision.

Assuming such an effect really exists, I expect it would be very difficult to statistically distinguish from straight heredity. Kids' early childhood habits tend to reflect family culture.

I read that being in the sun when you're a child and your eyes having to adjust with the change in brightness helps with reducing myopia

Perhaps a good reason to buy a HDR monitor then :)

The other hypothesis I've heard is that it's switching back and forth between focusing on close-up things and distant things. Which you naturally do a lot when engaging in outdoor activities, but basically not at all when staring at books or screens.

OTOH, perhaps those who are starting to have myopia aren't going to want to do outdoorsy things because they tend to require far-seeing. If I can't see what's going on far away, I'm not going to have a fun time with most sports, and I'd rather read a book.

Just read a book outside with reading glasses

Not sure if it'll help, there's an older gentleman on Youtube who claims reading with glasses actually makes myopia worse with time, due to the way it affects the shape of the eyeballs. Look up Tod Becker.

Really? We're taking medical advice from random people on youtube?

How is this any different from a youtuber claiming the earth is flat or vaccines cause autism?

I have hypermyopia (-12.5 left, -13 right) and my sister has 20/15 vision. Same childhood environment as her and I needed glasses before I could even read, let alone before I ever played a video game.

It's well beyond a genetic predisposition, it was a genetic guarantee for me.

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