[frankohn]

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

[digikata]

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.

[rmah]

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

[novok]

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.

[xwdv]

God no, UV radiation is a thing.

[magicpin]

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

[Franciscouzo]

And sunscreen is also a thing.

[xwdv]

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.

[throwawayboise]

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.

[soylentcola]

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.

[scythe]

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...

[Geee]

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.

[itwy]

I don't think it works like that.

[meowface]

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.

[soylentcola]

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).

[throwawayboise]

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.