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Comment by napoleoncomplex | Hacker News Reader

How does wearing sunglasses affect time outside effectiveness? Any research on that?

(Just something I've wondered since sunglasses are super prevalent)

My understanding is that the benefit of being outdoors is the ability and opportunity to regularly focus on things at a distance that helps, so sunglasses wouldn't factor in.

Isn’t that eye exercises?

It’s also exposure to natural light. Myopia jumps when kids are exposed to artificial lighting [1]. It seems some constant is hard coded into our genes to calibrate our eyes to the Sun’s light. (Artificial natural light, despite sounding like an oxymoron, can help.)

[1] https://pubmed.ncbi.nlm.nih.gov/38766340/

Yes, this is the main factor. Luminance and spectrum however are reasonable secondary factors and highlighted in the reference above.

That was the leading theory for many years that explained why adult humans today have much worse vision that humans of the not-so-distant past, but it was disproven in the last decade.

We don't yet understand why, but lack of exposure to sunlight is what causes still-developing eyes to grow incorrectly.

The issue isn't brightness, it's distance to what you are looking at and focus on the retina. When your eyes can still bring far objects into focus, they produce a signal that causes your eyes to grow longer. https://newsroom.uw.edu/news-releases/glasses-stop-myopia-ar...

I wonder if this is something VR headsets can eventually fix by putting things at a longer focal length?

Maybe instead of a 50” screen 24” away, a 500’ screen 240’ away.

Do we really need VR headsets for this? Is there some material way in which just walking around outside, for free, is worse than strapping expensive electronics to your face and staying indoors?

See sibling comment. If studies are right, the dominant factor is about one’s exposure to sunlight, not focal distance nor focal variation.

The brightness of light is actually believed to be the main factor now. This seems a supported by animal studies, where animals are fitted with light-filtering goggles. Animals that receive brighter light develop normally, while animals that receive dimmer light develop myopia.

Sunglasses are not just a fashion item they also protect your eye lens from gradual damage from UV. It may be a good compromise in the end.

Protection over a life time of exposure, whereas if you avoid myopia by age 20 you're probably good for life

Didn’t quite work in my case.

And you are not alone. I know a lot of people who got myopia after 20.

How bad? My college (8 diopters) was jealous of my "mild" 4 diopters of correction.

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