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0 pointsstevebmark5y ago0 comments

Your reply is a good example. I haven't seen anyone in this HN post's comments talk about how myopia works. I legitimately do not understand why so few people know even the basics of myopia progression. All of these comments are, pun intended, the blind leading the blind. I especially don't understand it given how common myopia is and how important it is for parents to understand it for their children.

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1. Glasses that blur what's on peripheral vision https://abc11.com/amp/4176773/

> too much time spent in front of a screen confuses the eye, since everything is in focus. The eye keeps growing, leading to myopia.

2. Glasses to stop myopia are successful in multi-site trial https://newsroom.uw.edu/news/glasses-stop-myopia-are-success...

Glasses with fogged edges prevent over focus:

> What’s supposed to happen as your eye grows, is that things should begin to go out of focus in the periphery of your vision. That’s a signal for the eyes to stop growing.

3. Multifocal contact lenses slow myopia progression in children https://www.nih.gov/news-events/nih-research-matters/multifo...

> Animal studies have shown that focusing light in front of the retina cues the eye to slow growth.

4. Putting contact lenses on monkeys _causes_ myopia and removing them slows myopia growth https://www.nature.com/articles/s41598-019-48009-3

5. "How Atropine Eye Drops Can Slow Myopia Progression" https://www.myopiainstitute.com/eye-care/how-atropine-eye-dr...

> Applying atropine eye drops dilates the pupils and temporarily paralyzes the focusing muscle inside the eye. It also relaxes the eyes’ focusing mechanisms.

Your eye grows without your brain's involvement. Sharp focus on the back of the eye, especially in the periphery, tells the eye to grow longer because it's overfocusing. This leads to the worsening of myopia. Things that cause sharp focus on the retina and fovea: contacts, glasses, and holding things close to your face that keep everything in focus. This may be why being outside is correlated with slowing myopia progression, because you wont have things constantly in focus in your peripheral vision from it being close to you.

I have a serious question: did you not come across any of this research? No one seems to have familiarity with these concepts in this HN thread. Did you see articles like these and skip over them? Or, maybe, were you only googling for myopia and sunlight, which is unlikely to return results like these?

0 comments

benibela5y ago

There is also a lot more research, see: http://www.myopia-manual.de/private/manual-2021-jan.pdf

>The development of chicks towards emmetropization was observed at various levels of illumination: (10.000 Lux, 500 Lux and 50 Lux). Result: After 90 days 50 Lux resulted in a mean myopia of –2.41 D, 500 Lux resulted in +0.03 D, and 10.000 Lux resulted in hyperopia of +1.1 D.

>"Categorized according to their objectively measured average daily light exposure and adjusting for potential confounders (age, sex, baseline axial length, parental myopia, nearwork, and physical activity), children experiencing low average daily light exposure (mean daily light exposure: 459 ± 117 lux, annual eye growth: 0.13 mm/y) exhibited significantly greater eye growth than children experiencing moderate (842 ± 109 lux, 0.060 mm/y), and high (1455 ± 317 lux, 0.065 mm/y) average daily light exposure levels."

>for myopic children 6 to 12 years old a mean progression of – 0.35 D in winter and –0.14 D in summer. This was attributed to the children's extended time spent outdoors in summer

Getting more sunlight is the most helpful thing one can do without special equipment

ubercow135y ago

Thank you, this is interesting!

>I have a serious question: did you not come across any of this research?

I hadn't seen the more recent developments on these preventative glasses, no. However I don't tend to give too much credence to individual studies especially when reported through mainstream media. You see such studies and articles supporting all kinds of contradictory conclusions all the time.

Wikipedia isn't a reliable source, but it is kind of useful as a quick overview of current ideas on a topic. Skimming the article,

>The near work hypothesis, also referred to as the "use-abuse theory" states that spending time involved in near work strains the intraocular and extraocular muscles. Some studies support the hypothesis, while other studies do not.[3] While an association is present, it is not clearly causal.[3]

and

>There is preliminary evidence that the protective effect of outdoor activities on the development of myopia is due, at least in part, to the effect of long hours of exposure to daylight on the production and the release of retinal dopamine.[15][29][30][31]

So, immediately it seems like we aren't so certain as you suggest we are what the cause of myopia is. And your assertion that "..exposure to light brightness has nothing to do with myopia" is directly contradicted here. And from a cited recent (2019) review paper [1]

> Huang et al. highlighted, in a recent systematic review and meta-analysis, that near-work activities were related with higher odds of myopia (odds ratio 1.14; 95% CI 1.08–1.20) and that the odds of myopia increased by 2% (OR: 1.02; 95% CI 1.01–1.03) for every one diopter-hour more of weekly near work [110].

> In contrast, there are studies reporting that near work is not associated with faster rates of myopia progression [85, 111–113].

> Therefore the relationship between near work and myopia is complex and needs to be investigated.

> On the other hand, several recent epidemiological studies suggest that greater time spent outdoors might have a protective effect against myopia development and progression [114–116].

So, though I am far from being an expert after reading these few articles, they all seem to strongly contradict your assertion that "It's not unknown", and also that the research all agrees with your points.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6875023/

stevebmarkOP5y ago

> The near work hypothesis, also referred to as the "use-abuse theory" states that spending time involved in near work strains the intraocular and extraocular muscles.

Goodness Wikipedia, this isn't the theory at all. It has nothing to do with muscle strain. We know for a fact that in youth, the eyeball grows longer when it's overfocusing (especially in fovea), and stops growing when things are blurry. That's how it maintain focus as you grow and age. This isn't a theory, it's how the eye works. There are already multiple types of technology that successfully slow and stop myopia based on this principle, as listed in my post.

The mechanism of outdoor light is just a hypothesis without known direct link. It may be related but there's no direct evidence for it yet.

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