[madeuptempacct]

https://www.npr.org/sections/goatsandsoda/2015/02/05/3837653...

There was a study that followed Chinese kids who stayed in China vs Chinese kids who moved to Australia. There was a marked difference.

Not sure if its about sunlight or near/far focus though.

[Apocryphon]

They can test this if they tried getting students to try studying outside under natural lighting for a while. Though in China that may be impractical depending on the city.

[lern_too_spel]

They tested having students study in a sunlit classroom. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5536284/

[jacobolus]

> Not sure if its about sunlight or near/far focus though.

I have seen some suggestion that it is a combination of both. Either is plausible though.