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Comment by lmm | Hacker News Reader

On the contrary, there's nothing people love more than blaming any problems on what the kids these days are enjoying, regardless of evidence.

The evidence is actually pretty clear, what's causing this vast increase in myopia is not spending enough time in bright environments (i.e. outside) during one's formative years. In that regard cellphones (since they can be used outdoors) are a huge improvement over e.g. television.

If we actually cared about fixing the problem, we'd be making it easier for children to spend time outside and making outdoor environments more welcoming for them. But that would require parents to allow children some freedom, or maybe even actually make some lifestyle changes of their own, whereas the revealed preference of parents is to lock their children up indoors all day and night doing something that looks like "studying" (i.e. pointless drills).

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> what's causing this vast increase in myopia is not spending enough time in bright environments (i.e. outside) during one's formative years.

I'd like a source on that. AFAIK the leading factor is so called "near activities", or more specifically, lack of "far activities" (i.e. lack of looking at a distance, which makes your eyeballs get and keep proper shape and characteristics).

> In that regard cellphones (since they can be used outdoors) are a huge improvement over e.g. television.

Again, environment brightness, AFAIK, is way less important than the distance at which you are looking. Hence, looking at the TV is better than at your phone. And I suspect both are better than reading a paper book.

https://pubmed.ncbi.nlm.nih.gov/34142457/

No that's not it at all. It's amazing how people in this thread act like this is a new frontier in health care or something, thinking that genetics and exposure to light are the causes.

It has been determined very conclusively that myopia is caused by spending too much time looking at close objects. That was in my highschool textbook like 20 years ago.

Yes kids should spend more time outside but it has nothing to do with bright environment.

But is it the intensity and spectrum of the light or the fact that being outdoors means your eyes are looking at far more distant objects?

It's purely the brightness. If you're in ambient bright light you don't develop myopia even if you're looking at nearby objects the whole time (e.g. reading books or a phone), if you're in a dim environment you still (are at statistically elevated risk to) develop it even if you're looking at distant objects. This is something they've had to keep doing bigger and bigger studies on because everyone who hears about it has the same kind of thoughts as you did.

OK. A dumb question. So I've been using dim screen brightness to my computer monitor every since I started using glasses. Should I be increasing screen brightness?

Cos I am very serious about having proper lighting on the room I work in. But always thought the screen should be dimmer than the room for some reason.

The short answer is I have no idea. As a matter of personal speculation, I doubt screen brightness makes much difference compared to the huge range that ambient light level can have (about four orders of magnitude IIRC). Most screens look bright at night even on their dimmest setting, and are too dim to read in sunlight even on their brightest setting.

Interesting. Mine has been the least possible brightness with which I can read. Just turned it up a notch to match the room brightness. Let me experiment with it for some days.

Thanks for taking the time to share your POV.

Wouldn't it be brighter settings = less stressom focusing muscles because smaller pupil = higher depth of field.

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