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