I was thinking about myopia while working out at the stair master on the gym. The way they are positioned, it forces you to have to look at people. Not bad if there's a cute female in spandex, but I don't really want the other 80%. I find that if I don't wear my glasses (20/1000) then I suddenly get a lot less anxious as everyone kind of blurs. If they are looking at me, I don't notice.
As others have commented, our society constantly tries to focus our vision on a very narrow range. The computer screen. The TV screen. The windshield. The billboard. The boss. The President. We are directed to "look this way" and "pay attention". But obviously in smaller towns and primitive societies, we spent most of our time inattentive. Taking it all in. And what do we do to "relax"? Take a drink (or whatever), and let our mind release and float.
I wonder if it was possible to survive with nearsightedness in a primitive or even rural society? Maybe it's possible to focus without 20/20 vision. Hunting. I wonder if it's better to defocus so you can see where the buffalo is on the plain. And so on...