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Shortsightedness has become an epidemic

economist.com

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Re: Shortsightedness has become an epidemic

#391

Post by thaumasiotes »

throwaway202022 wrote: post #310
thaumasiotes wrote: post #203

Earlier quoted context omitted.

> Mine is genetic. > I have very simil[a]r values than my mother. Well, everything is genetic. The amount of sunlight you're exposed to is no less a genetic effect than how tall you grow to be. Without genes, you wouldn't have any behaviors or phenotypes at all. So the interesting question is not "is this phenomenon genetic?", because the answer to that is always "yes". The interesting question is "what can influence…

This is 100% true. Genetic predisposition to something != inevitability.

> Genetic predisposition to something != inevitability.

That depends on the thing. Whether you grow five or six fingers on your hands is determined by your genes without much reference to anything else. Whether you reach a "natural" height or develop stunted by malnutrition is also determined by your genes. It is more responsive to environmental conditions than the number of fingers on your hand is - but that responsiveness is determined by your genes.

Re: Shortsightedness has become an epidemic

#392

Post by alanh »

californical wrote: post #318
tominous wrote: post #184

Earlier quoted context omitted.

Not denying that there are many ways in which development can go wrong, whether that's genetic or the environment. What I'm responding to is the sudden change seen in many populations as per the article. Re: the chromatic aberration spread, see e.g. https://pubmed.ncbi.nlm.nih.gov/3716229/ They measured 1.82 diopters between 420nm and 660nm. Visible light is a bit wider, 380nm to 720nm, so 2 diopters is about right.…

Huh, I always wondered why blue LEDs that were further away would be hard to look at & make me dizzy, that’s crazy!

Pure blue light does the least to stimulate the rods that help you see shapes clearly, only activating blue cones. This is why compression algorithms and some screens use 2 or 4 times as many bytes or phosphors for green as they do for blue https://biodifferences.com/difference-between-rods-and-cones...

This is also why writing a word in pure blue neon lights is really dumb. Adding just a little bit of green to it helps readability immensely.

Re: Shortsightedness has become an epidemic

#393

Post by EnKopVand »

volfied wrote: post #207
EnKopVand wrote: post #201

Earlier quoted context omitted.

The beauty of science is that you don’t have to “believe” in it.

The beauty of science is that you don't "blindly believe" in it.

Well obviously, but that is not the counterpoint to what I was saying at all. If you see science that you don’t “believe” is true, then you need to do science to show us it isn’t true before speaking out about it. Maybe not everywhere, but at least here on HN people still prefer to take reason and proof over anecdotal stories from your undocumented and limited experiences.

Please note that I don’t mean to say your anecdotal experiences can’t be interesting, just that they can’t be used as science until you do the work to actually prove that they aren’t just your experiences.

Re: Shortsightedness has become an epidemic

#394

Post by viktoracoric »

EnKopVand wrote: post #393
volfied wrote: post #207

Earlier quoted context omitted.

The beauty of science is that you don't "blindly believe" in it.

Well obviously, but that is not the counterpoint to what I was saying at all. If you see science that you don’t “believe” is true, then you need to do science to show us it isn’t true before speaking out about it. Maybe not everywhere, but at least here on HN people still prefer to take reason and proof over anecdotal stories from your undocumented and limited experiences. Please note that I don’t mean to say your an…

Well if scientific paper contradicts the observable experiences from the real world, then obviously something went wrong during the experiment.

And you still believe in this paper because you didn't reproduce it yourself or you didn't see it being reproduced step-by-step in real life, you rely on this scientist who conducted the experiment reporting it legitimately and other scientists involved in peer review process to have actually read the paper and verified it through reproduction (which isn't all too common in academia btw.)

Re: Shortsightedness has become an epidemic

#395

Post by ymolodtsov »

Hellicio wrote: post #175
tominous wrote: post #149

Almost all children are born hypermetropic (far-sighted). The growth of the eyeball is calibrated by the amount of defocus (blur) experienced. More defocus, more growth, which reduces hypermetropia. My hypothesis is that less sunlight means wider pupils and more defocus (contrast to a pinhole camera), so more eye growth. Even with perfect eyesight, there's a 2-diopter difference between focussing blue light and red l…

Mine is genetic. I have very similiar values than my mother. So i'mnot sure if / how your theory is correct or not. Also there are a lot of normal people in the world who live outside and also don't have perfect eye sight at all. This goes back a long time. Can you also elaborate on your 2 diopter difference between red and blue light? For one i find that number very very big but i'm very good in seeing full color wi…

I think there's genetic predisposition but unless you have a separate disease, myopia is unlikely to just emerge out of thin air. There's probably something that we do that harms our ways and the studies point to the time outside as the key factor (screen time was just a correlation).

Re: Shortsightedness has become an epidemic

#396

Post by ymolodtsov »

alanh wrote: post #392
californical wrote: post #318

Earlier quoted context omitted.

Huh, I always wondered why blue LEDs that were further away would be hard to look at & make me dizzy, that’s crazy!

Pure blue light does the least to stimulate the rods that help you see shapes clearly, only activating blue cones. This is why compression algorithms and some screens use 2 or 4 times as many bytes or phosphors for green as they do for blue https://biodifferences.com/difference-between-rods-and-cones... This is also why writing a word in pure blue neon lights is really dumb. Adding just a little bit of green to it he…

I'm really interested in this topic since I've always noticed this, but not sure about this explanation as to why. I mean, yes, Bayes filter is like 2x1x1 for green, *red* and blue, and the most popular explanation has always been that our eyes perceive green better than both red and blue. Yet I don't have issues with red LED lights.

Re: Shortsightedness has become an epidemic

#397

Post by sandstrom »

nickbauman wrote: post #220
sandstrom wrote: post #192

For several decades it has been known that myopia (nearsightedness) and intelligence are correlated[1][2]. Initially it was speculated that reading caused nearsightedness, and through that higher intelligence. There is probably some truth to that. But with modern DNA sequencing techniques researches has found genes that seem to affect both[3][4]. The hypothesis is that one (or a set of) genes affects both eye size gr…

I thought the increase in nearsightedness originated in kids not playing outside as much (and thereby not focusing their eyes over longer distances) resulting in eyesight that's more attuned to shorter distances.

Yes certainly, that (and many other things) are more important factors. I'm not trying to say this is the only (or even a major) cause.

But that doesn't make it less interesting of a fact.

Re: Shortsightedness has become an epidemic

#399

Post by ymolodtsov »

Aulig wrote: post #325

Honestly, myopia is not complicated (Kepler pretty much had it right in 1604 already). There's countless studies showing that axial length (eyeball length) changes in both directions, where elongation increases myopia. How do you change it? You get defocus (blur) which makes the eye adjust in the direction to reduce the blur. Practically: use weaker (around 1.5 diopters) or no glasses during close-up work (reading, c…

That's outdated advice popular among doctors like 30 years ago. No credible specialist would tell you to wear weaker glasses in 2022.

Re: Shortsightedness has become an epidemic

#400

Post by ymolodtsov »

Aulig wrote: post #370
alar44 wrote: post #365

Earlier quoted context omitted.

There's just no evidence for it. It's that fucking simple.

No evidence for what? Almost everything related to endmyopia is proven, aside from the whole thing put together. The main thing, axial length reduction through undercorrection, has been shown in plenty of animals and humans.

Come on, it hasn't been proven on humans.
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