I've read a number of anecdotes about benefits of bright, full-spectrum indoor lighting and I'm increasingly sold on the idea.

The only thing that makes me hesitant is the extreme unpleasantness of direct high brightness artificial light. I wonder if an indirect lighting setup of similar brightness could be as effective.

It is. The best I've seen make use of essentially bright overcast levels of lighting, so more like 2000 lux, and it's extremely pleasant.

This guy has a pretty compelling version:

https://www.youtube.com/watch?v=6bqBsHSwPgw

If you look at his scatter pane, that's where I would go. There are companies that sell similar lights retail, but they're perhaps 3x as expensive.

I'm not sure why you're convinced that focusing distance is irrelevant. Everything I've seen indicates that it is the combination of focusing distance and light level.

Also... 100x the lighting indoors strikes me as quite difficult? Do you have any examples of a realistic setup?

Think operating room or photo studio. 100w grow light panel for every 2-3 square meters - so for a typical office, 4 100w lights, with a scatter panel in front.

I really like this video for an example of how to make proper scattering effect, but you can buy similar materials that are more durable and lighter, for in e.g. a drop ceiling:

https://www.youtube.com/watch?v=6bqBsHSwPgw

That's a cool video, but a custom 500W water-cooled setup does indeed strike me as "quite difficult" for your average person. It seems that the LED in the video is the $500 YujiLEDs BC270H, which is 20,000 lumens. In other words, to match midday sun at ~120k lux, for a small room of 100 sq ft /~10 m2, where all light fell directly onto you/the floor and none on the walls, you would need 1.2 million lumens, or _sixty_ of the setups in the video, or about 30 kW continuous ignoring all cooling needs and other losses.

I completely believe him when he says that it feels like sunlight (it's a high-quality, high-CRI, extremely bright light source at infinity!) but us humans are very bad at determining brightness levels. An iPhone flashlight in your face is unpleasantly bright and yet it is a completely insignificant amount of light on an absolute scale. We humans perceive brightness on a sort of relative log scale.

The steelman argument - where someone does indeed build one 500W water-cooled setup with large dish etc - and all of this light falls into a small corner of 2m x 2m - is still only ~5000 lux, roughly an overcast day. To even get to the level of standing in the shade on a clear day - 20k lux - for a regular room, you would need an obscenely powerful setup.

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The natural response to my comment, of course, is that "well, maybe they don't need those high levels!" The problem is that all of the research indicates that they do. You mention research on Taiwan, which I think is a perfect example. They already did try to brighten the indoors to prevent myopia - minimum government standard of 500 lux starting with a 1999 standard [1], and in many cases brighter than that. You say that they need a 1000 lux environment, which isn't much different than the current Taiwanese indoors. I, on the other hand, say they need a ~100k lux environment, which is orders of magnitude more light. The research agrees with me: it was not the 500 lux standard, but the later introduction of two hours outdoors daily that improved myopia rates [1,2.]

Mind you, this is two hours outdoors during school hours in Taiwan, which is near the Tropic of Cancer (think Mexico, Caribbean, North Africa) and thus has far sunnier winters (Taiwanese peak summer sun is 1.9x winter sun vs 4.2x in Boston, 3.7x in NYC, 10x in London [4]) despite total solar irradiation being similar to Western cities [3.]

[1] https://www.sciencedirect.com/science/article/pii/S016164202...

[2] https://pubmed.ncbi.nlm.nih.gov/34425129/

[3] https://solargis.com/resources/free-maps-and-gis-data?locali...

[4] https://weatherspark.com/y/137170/Average-Weather-in-Taipei-...

Because studies that controlled for focus distance (ie compared children reading indoors v children reading outdoors) seemed to show that focus distance did not have an impact.

Late reply, but most of the pro-focusing-distance crowd agrees that it’s time in peak sun, plus a fairly small number of daily “reps” of near-far focusing that is sufficient. In other words, kids could spend 99% of the time outdoors just reading a book, and the handful of glances at a tree in the distance, stop sign, bird, etc would be sufficient. Furthermore, as I mentioned to a sibling comment, even if it is just the bright light, with no influence from the focusing (which I doubt!) the only practical way to get that light is outdoors.

Solving focus distance is expensive. If you could prevent this with something cheap, why not ?

The intervention that most advocate for is shifting kids’ breaks to be outdoors during peak sun hours. This is free ($0.) You get 100k lux, high CRI, flicker free light with no power or setup requirements. You also get birds, trees, buildings etc in the distance as “infinity” focus targets, also for free. (Reminder that “infinity” is actually fairly close!) This approach is also proven to improve myopia rates.

Custom water-cooled ultra-powerful indoor lighting setup as suggested by sibling comment: $30k/small room (far focus not included)

Interesting, it seems really likely that more light indoors should be good. Do you have a reference, a scientific study on the topic? Thanks!

It's difficult for artificial light to compete with full-spectrum natural daylight from an infinitely distant light source (sun). See previous attempts at sunlight simulation indoors.

Here's a couple from a random search for the convenience of the forum:

https://pubmed.ncbi.nlm.nih.gov/29371008/

https://reviewofmm.com/light-as-a-tool-for-myopia-control/

I can't find the site that I read a while ago, it was very similar to the myticker.com site that was posted the other day for heart disease but focused on myopia.

Thanks for sharing this! I've never heard of this research, but it sounds very promising.

I also found this Guardian article from a Google search: https://www.theguardian.com/world/2025/mar/01/shortsighted-t...

I have fairly bad myopia (-6) and I was outside a lot as a kid. I don’t buy this argument, at least not universally.

And I had fairly bad myopia before I could read or had ever seen a computer, would you like to reject the argument that reading or screens are relevant as well?

Practically nothing in health science is universal, your anecdote does not disprove anything.

I wonder, wouldn't this mean that in nordic countries, where in winter get less than 6 hours of sunlight in total, and where that sunlight is mostly obstructed by heavy clouds, would be the place with most myopia in the world? For example in Latvia where I grew up, winters last from november to march-april, the nights are long, and it can be months without any sunlight. And it gets darker once you go further north - Finland, Norway, Sweden. But back in my preschool, we had 1-4 kids per 30 in the class, with any eye problems. I myself was among those few who had hypermedia, some even got rid of it by age 10-13. And if I look at the my parents, and grandparents - even fewer had need for eye correction.

Genetic adaptation of humans is a thing.

One way to test it out would be the rates of myopia of people from lower latitudes that have migrated to the nordics.

Valid point. I guess then in Canada they could have a lot of such cases, as it has been a major destination for migration. In any case, sounds like an good topic for a research paper

>> Dimmer light makes the eye think it isn't done growing, so it grows more.

Does that mean that populations in places with more sunlight (e.g. close to the equator) have less myopia than populations with less (e.g. close to the arctic)?

Yes, and the difference is pretty significant, but early childhood schooling rates are more significant than latitude alone.

https://nap.nationalacademies.org/read/27734/chapter/5#29

That's interesting. I seem to be the only one around my circle who like bright environments (my work area uses 2 2400 lux lamps). I find most environments too dark.

And I'm the only one who doesn't wear glasses, lol