[bilegeek]

The factors weren't "childhood eyestrain and video games". The one consistent factor was the amount of bright light exposure in a study[1]; in other words, being indoors, away from bright sunlight, which is correlative to eyestrain and video games, not causative, because people tend to do those things indoors. If you read outdoors in bright light, it's not really worse than just hanging around in bright light.

Couldn't find a non-paywalled PDF, sorry, but here's the original study:

[1]https://www.thelancet.com/journals/lancet/article/PIIS0140-6...

Also, it might have changed since then (2012). If there's since been a study refuting this one, let me know, because it's nigh-impossible to find between the glut of citation-free news sites and blog posts, and paywalled journals.