Comment by benibela

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