Considering how much it would’ve affected hunting and gathering, how are so many people nearsighted?
In: Biology
The vast majority of nearsightedness isn’t very strong. It can hurt the ability to read tiny letters or make out small details, but those aren’t really needed for hunting or gathering.
Also, reading or looking at screens a lot during childhood, when your eyes are still developing, cause cause or worsen nearsightedness. It’s a lot more common in modern society than it was back when hunting and gathering was a significant factor for the average person.
Only if that myopia was so severe that it prevented reproduction. Natural selection works on removing traits that prevent the individual to reach reproductive age, otherwise those genes just keep passing on.
The main causes of myopia are things like spending lots of time indoors and spending hours reading – both pretty recent developments in human evolution.
Nearsightedness isn’t that much of a disadvantage, really. I’m nearsighted, but I can safely drive without glasses or contacts. I assume I can see well enough to hit the broadside of a deer with a spear.
I believe the current understanding is that inadequate exposure to daylight as a kid really increases the chances of myopia. So it’s not that reading and screens hurt the eyes, its that they replace playing outside. Just like being in school, actually.
Near-sightedness is in large part an acquired condition due to too much close-in reading during childhood. Your eye ball grows longer to accommodate close in work at the expense of distance vision.
Fortunately, by the time society required children to spend hours a day reading, they also invented glasses.
I’m super near-sighted and I think about this all the time…..I can barely survive in my home without contacts/glasses. I for sure would have died 200 years ago……I can’t tell the difference between shadows on the ground or holes
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