Well specifically to the brightness, how much light is going into your eyes when using a VR set relative to, say, a TV? Or a 27-inch monitor close to your face?
I mean there’s probably a pretty strong correlation between being outside and having a long focal distance, but my understanding was that when attempting to control for this (ie rise of increase in apartment living, first in Japan and then other Asian cities) its tightly correlated to not focusing on things a long way away