Memes

My understanding is that being nearsighted is a relatively new phenomenon that is largely due to being indoors a lot. Farsightedness in old age has been around since humans have been humans.

I took a quick look and Wikipedia partially bears this out re: nearsightedness.

I think its a bit of both.

Personally, I apparently focus (that's what it's called, right? Non native speaker here) slightly behind infinity, so I'll have to put a slight amount of effort into seeing clouds clearly. I can also focus on close objects, but if I read a book for about 5-60 minutes without my glasses I'll suffer a splitting headache, depending on how much time I've used inside recently.

I've found that I can do office work just fine using glasses, but after a few months I'll need to get stronger glasses as my eyes become worse. This resets if I spend a few days outside avoiding computers, books, and my glasses entirely.

I can usually watch TV just fine without glasses, but if I've been doing office work or just been mostly inside for about 2-3 months I'll need my computer glasses (tuned to focus at around 50-100cm) to watch the TV (located about 3 meters away). At this point, I usually also have to use my reading glasses for the computer, and I've got a special pair of glasses that I can use for reading in that specific case. I even start having problems driving longer routes.

In other words, I have ~~really~~ rather (I can still most tasks, just with a headache) bad eyesight during winter and spring, but usually have much better eyesight and barely need glasses during summer and fall.

There are a few ways to have bad eyesight

• Short sighted, can only focus close up
• Long sighted, cannot focus close up
• Poor acuity, cannot see the detail others can see
• Colour blindness

It looks like most of the short sightedness is caused by lifestyle since it is much more prevalent in places where children spend a lot of time indoors

The others would have affected our ancestors as much as us

There is some truth to it, but there's also just the fact that some people's eyes are bad enough that they need glasses to fully function in modern society, but not so bad that they couldn't survive in the wild without them.

Me for example. I need glasses to drive, I can't read street signs otherwise, and I need them at work, but I otherwise usually don't wear them. The only thing better eyesight would meaningfully help me with in the wild is navigation and spotting hidden animals quicker, and even then it'd really only help with snakes. Any other ambush predator I'd be likely to encounter in my region is big enough that spotting it a few seconds sooner wouldn't really help.

OP is right, nearsightedness has been attributed to "not being outside enough" while your eyes still develop (aside from genetics of course), something to do with not getting bright enough sunlight for multiple hours as you are supposed to.