How does sunlight reduce myopia (near sightedness)?

[Solarscout]

Research shows that exposing children to more sunlight can reduce myopia. Myopia is caused by elongated eyes, so it suggests that sunlight can help keep eyes round and spherical?

https://www.aao.org/education/editors-c ... n-children

Study design
Researchers recruited grade 1 school children from 16 different Taiwanese schools. Of the 693 students included, 276 were encouraged to spend 11 hours/week outdoors through a school-based program. The remainder of children were in the control group and continued regular activities.

Outcomes
Light intervention reduced both myopic shift (0.35 D vs. 0.47 D; P=0.002) and axial elongation (0.28 mm vs. 0.33 mm; P=0.003). Risk of rapid myopia progression was also 54% lower in the intervention cohort compared with controls. Effects were significant in both nonmyopic and myopic children.

Investigators noted that longer exposure to moderate sunlight intensity (i.e., hallways, under trees) was as effective as short exposure to high sunlight intensity for preventing myopia.


But the study doesn't seem to explain how the Sun can keep your eyes healthy. Can you speak from personal experience whether being out in the sun longer keeps your vision better for longer?

[pupak]

I personally believe that the children were mainly helped by being outside and not staring at monitors and mobile phones, which are the main cause of poor eyesight. Our eyes need natural light. They are projected onto him.

[marktownley]

Interesting!

[Carbon60]

Maybe the smaller pupil in brighter light produces sharper images, so eyes aren’t struggling to focus so much….less eye strain.

Who knows?

Interesting though.

Stu.

[GreatAttractor]

I personally believe that the children were mainly helped by being outside and not staring at monitors and mobile phones, which are the main cause of poor eyesight.

I can't find the link now, but I read an article which indicated that computer/phone use doesn't seem to matter. IIRC, they compared myopia prevalence in children & teenagers between Western European countries and South Korea, with both having similar screen time, but much less outdoor activities - and more myopia cases - in SK. The conclusion was that regular exposure to UV in sunlight is crucial for proper development of the eyeball.

But as always, things are complex, here's a Korean study on myopia prevalence discussing (no hard conclusions) some factors: link.

[pupak]

I can't find the link now, but I read an article which indicated that computer/phone use doesn't seem to matter. IIRC, they compared myopia prevalence in children & teenagers between Western European countries and South Korea, with both having similar screen time, but much less outdoor activities - and more myopia cases - in SK. The conclusion was that regular exposure to UV in sunlight is crucial for proper development of the eyeball.

But as always, things are complex, here's a Korean study on myopia prevalence discussing (no hard conclusions) some factors: link.

Life has taught me that every study has such a result as the client pays for. During my childhood, two children from my class had glasses, today it is 7 out of 10 in the Czech Republic.