This is def a decent counterpoint - on a previous HN thread on this topic I recall studies being done on agricultural vs urban mainland chinese people and how a

This is def a decent counterpoint - on a previous HN thread on this topic I recall studies being done on agricultural vs urban mainland chinese people and how a refinement to the observation so sunlight/outdoors might be a proxy for some other factor. I've seen proposed "distant viewing". Although one possible nuance is that sunlight to the eyes != sunlight to the skin. In cold climates you wear thick clothes which will block out sunlight to the skin (vit D deficiency) but you may still get plenty of UV to the eyes. Throw in some mountains for distant gazing and suddenly nations that love skiing could be simultaneously vit D deficient but guarded against myopia. Pure conjecture of course - IANA(Biologist/Opthamologist/Doctor)