I used to read theories about what causes near-sightedness, whether it was spending too much time in the dark, or reading small text, or sitting too close to the TV (my parents' favourite theory), or whatever the pop theory of the day is. But the older I get, the more convinced that I've just had bad luck with the genetic lottery.

I don't think that environmental factors have as much of an effect as people think. Genetics and luck play the biggest part.

Indigenous populations (of most colonised countries) tend to have far lower rates of nearsightedness compared to Caucasians, despite living in the same environment. I think that maybe myopia was much more disadvantageous in Indigenous environments with an emphasis on hunting and traveling across wilderness than it was in Europe, with all its cities and roads. The ability to spot animals and landmarks from a long distance is much more important in areas with large open spaces, like the American Plains or Australia's interior, than it is in more densely forested and populated areas like Europe.