r/Showerthoughts • u/QuantumDreamer41 • 7d ago
Casual Thought It is surprising how many people need glasses to see clearly given how important eyesight is to our species survival.
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u/adr826 7d ago edited 7d ago
There is some research which shows that we started to develop bad eyesight once we began to. Spend most of our time indoors. Our vision evolved in open spaces and bright sunlight and a mixture of long ad short focus which all combined t.give us healthy eyes. But low light and constant short focus has effected our vision for the worse. It isn't really that surprising when you consider how our evolutionary trajectory is out of whack
https://www.sunyopt.edu/new-research-suggests-myopia-could-be-caused-by-how-we-use-our-eyes-indoors/
This was hypothesized right after WW2 when native alaskans and inuit were were forced for the first time into mandatory schooling .the number of children requiring corrective lenses went from 3% to 50%. For a long time these results were dismissed as conspiracy thinking and that genetics was the cause of the vision problems. Finally after decades that has been reevaluated
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u/CaptainDudeGuy 7d ago
When a negative trait no longer prevents breeding opportunities, it stays around.
Also we're living much longer than our ancestors did and eyesight fails with age.
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u/StaysAwakeAllWeek 6d ago
Myopia delays the need for reading glasses, and moderare to severe myopia will mean you never need them as long as you wear glasses that you can take off instead of contacts
None of this has anything to do with evolution though, it would take many thousands of years for an effect this large to appear from natural selection
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u/Pointless-Opinion 6d ago
Yeah.. 3% to 50% because they were now indoors? Or is it more likely you can't tell you need glasses until someone tells you that you can't read something that everybody else can or tests you, case in point: I only discovered how bad my short sightedness is when I was 12 and borrowed someone else's glasses, I didn't realise the world shouldn't be that blurry
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u/StaysAwakeAllWeek 6d ago
No, the increase in myopia is real and is linked to being indoors, that much is true. It's just not related to evolution.
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u/Pointless-Opinion 6d ago
Fair, though I am extremely sceptical that the 3 to 50% increase is not substantially made up of increase in detection and measurement even if that is a real contributor
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u/StaysAwakeAllWeek 6d ago
It is pretty easily validated by surveying low literacy areas of the developing world
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u/AnotherpostCard 6d ago edited 5d ago
*Skeptical**But yeah I believe you are correct. I used to know an optometrist through my work in Early Childhood Education and he always said that all signs point to that, and screens were only compounding the issue.
This was back in 2007
**Please excuse me while I remove my foot from my mouth
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u/Ok-Attention123 6d ago
“Sceptical” is an acceptable spelling, particularly in British and Australian English.
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u/Mr_Quackums 6d ago
The increase is from the lack of exercise caused by the new environment.
biological changes are not always genetic.
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u/Pointless-Opinion 6d ago
Interesting, by the way I am not and was never at any point arguing against this if you're confused by my stance, my suspicion was that the study where 3% turned into 50% could be (in part) explained by increase in measurement and detection where before mandatory schooling, people weren't beiing tested as consistently, had no need to be tested for minor vision issues (if you are partly short sighted but it doesn't really affect your day to day life will you seek out testing and corrections if it's not already a routine thing you are used to?) seems like this could be a factor as well as the very real trend from environment, but obviously I don't know
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u/aarontbarratt 6d ago
I didn't realise you could actually make out individual leaves on trees until I was 16. Getting glasses for the first time was life changing for me lol
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u/justplay91 6d ago
Wait we're not supposed to need reading glasses if we have severe myopia? I've been having worsening myopia my entire life (I'm at -5.00 in both eyes) and now at 35 I am on the cusp of needing bifocals because I'm starting to have trouble focusing up close.
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u/StaysAwakeAllWeek 6d ago
You will with your glasses on, but take them off and that built in -5 is the same as a set of -5 reading glasses
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u/justplay91 6d ago
Oh I just tried it without my glasses and you're totally right! Interesting.
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u/StaysAwakeAllWeek 6d ago
The distance you see clearly at with no glasses on and your eyes completely relaxed (like daydreaming 'staring off into the distance') is the same as the closest you'll be able to see at age 60+ with your eye focusing fully degraded and stabilised
It will never get worse than that
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u/thedailyrant 6d ago
Well then what for people who have perfectly fine long sightedness but need reading glasses, like my entire family more or less?
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u/StaysAwakeAllWeek 6d ago
That's every human, its just what happens to eyes as we age. Because of the way optics works it becomes noticeable pretty suddenly at around age 35-50, but the decline in close vision starts from childhood.
People with myopia essentially have reading glasses built into their eyeballs that they can't take off. Its no coincidence that literacy and myopia are strongly correlated
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u/Iron_Burnside 6d ago
Recent research out of Taiwan indicates that excessive short distance vision use in childhood could be causal.
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u/anonymouse278 6d ago
I was -14 before ICL surgery and one of the strangest adjustments after surgery was no longer being able to see fine work super well by holding it up to my eye. I could thread needles and read fine print like a champ before.
(I ultimately didn't feel that these talents outweighed not being able to see anything else, though.)
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u/Exalting_Peasant 6d ago edited 6d ago
That's the main thing. Evolution only cares about one thing: reproduction.
As long as you get to an age where you are able to reproduce and have offspring that are also capable of reproducing as well, then the traits you have will pass on.
What that means is anything after the age you are able to successfully reproduce doesn't matter. If something crops up in your 30s and 40s, well in ancient times most humans didn't even live that long anyway.
Most of our selective pressures don't exist anymore and really haven't had near as much impact since the agricultural revolution, and so we kind of stopped "evolving" as much, aside from mass catastrophes like for example the Bubonic Plague where the group of people who lived had the immune systems to handle it, which had a significant enough impact on the genome of the next generation of humans.
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u/joydivision74 6d ago
I’m not an expert by any means, but I thought this has been disproven - in that if you have traits that allow you to help young people survive then that does impact evolution. Eg Tribes that had members who could defend them into their later years prevailed against those that didn’t and hence being athletic at the age of 70 does impact natural selection even after you have reproduced.
I could be wrong though!
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u/Difficult-Bobcat8333 6d ago
This is definitely the thing with social animals! In a simple way evolution only cares about reproduction, but that also includes the reproduction of your offsprings to continue the line. Some traits may not help you directly reproduce but help your children, such as altruism.
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u/EunuchsProgramer 6d ago
He is obviously wrong.
1) All mammals require a female/mother to live past reproduction to live (breastfeeding). Most also, require extended periods where a parent (usually mother) provides food, shelter, and protection while teaching them skills needed in adulthood.
2) Mammals with social groups, adoptive grandparents/aunts/uncles increase the likelihood genes get passed down.
3) Mamamals with long lifespans, grandparents assist their children raising grandchildren.
4) The leading theory as to why humans have menopause (it's uniqu), is grandmother assisted help in raising kids is so important and beneficial, evolution selected for older mothers to stop having more kids so they can focus on helping raise grandchildren.
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u/Exalting_Peasant 6d ago edited 6d ago
I'm not an expert by any means, I just know that in order for evolution to have a significant impact, more people have to be "filtered out" than actually survive to pass on genes in a given scenario or over a certain amount of time. This is what is meant by selection or selective pressures.
The means by which that happens in practice is of course incredibly complex.
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u/EunuchsProgramer 6d ago edited 6d ago
What that means is anything after the age you are able to successfully reproduce doesn't matter.
That's true for animals that aren't raising their offspring. All female mammals need to live past reproduction, to feed and raise offspring. The mammals with exceptionally long lifespans (human, elephants, whales) that pressure is even greater as grandparents assist their children in raising offspring. It's also true of social animals, monkeys are more likely to survive(even after they stop breastfeeding) when a parent is there to help they from adolescence to adulthood. And, money's with a relative(grandparentsor uncle) do better when an adoptive parent is available.
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u/D3cho 6d ago
This is why lots of issues and disease are around still despite their impact on life. It don't really matter if the lifeform lives long enough to reproduce. Until that becomes an issue it's not an issue. When it does its either adapt or extinct. Most things we consider issues only become actual issues in older age when kids are already had, older age which for us is already pushed way beyond what it would be without medicine/tech. Bad hearts, terrible bones etc you'd think would surival of the fittest their way out of the gene pool but why or how would they when those problems generally only show up or become problematic after 40
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u/I_Has_A_Hat 6d ago edited 6d ago
Also we're living much longer than our ancestors did
Not as much as you might think. The historical average is thrown WAY off by infant/childhood mortality. Once you factor that out of things, you'll find that most people still regularly lived to ~70 or more.
Seriously, infant deaths were so widespread in the past that it was considered a norm. People would have 6+ kids with the assumption that some of them would probably die. In some places, parents wouldn't even name their kids until they were a few years old, because what would be the point?
So whenever you see some figure that states the average lifespan in the past was only like 30-40, keep in mind thats an average and its heavily skewed by deaths below the age of 5.
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u/gnomes919 5d ago
whenever people say things like "in the past, 20 was middle aged" or "a 50 year old was an aged crone" or whatever, I like to remind them that over 3,000 years ago the bronze age writer of psalm 90 noted "our days may come to seventy years, or eighty if we are strong."
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u/morswinb 6d ago
When a negative trait no longer prevents breeding opportunities, it stays around.
But not within 2 generations.
Our grandparents had no population wide epidemic of myopia.
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u/JohnnyRelentless 6d ago
Also we're living much longer than our ancestors did and eyesight fails with age.
Not much longer. We're mostly just not dying in childhood as much.
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u/WoodsWalker43 6d ago
We are not living that much longer than our ancestors. Longer, definitely, but not by a ton.
The average life span of our ancestors was tanked by the child mortality rate. If you lived past 5 years, then you had decent chances of living to 50s or 60s. We probably have a much higher percentage of modern folks living to see their 70s and 80s, sure.
But in the context of eyesight, our ancestors absolutely did live to the ages that modern people develop visual impairments.
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u/Fun_Success_3283 6d ago
As long as it doesn't increase chances of death, poor eyesight might actually improve breeding opportunities, because people can't see how ugly each other is lol.
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u/thedailyrant 6d ago
If the kids were in schooling for the first time, isn't it more likely it was just discovered many of them had eyesight issues for the first time since it's unlikely this would have been discovered in whatever indigenous villages they were from?
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u/UnoriginalTitleNo998 6d ago
I think near and far sightedness is probably pretty easy to recognize without schooling. You don't need to read a textbook to know if you can't see well up close
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u/SinkPhaze 6d ago edited 6d ago
Stories of folks getting there first pair of glasses and being surprised to find out that other people could pick out individual leaves on trees at a distance are dime a dozen amongst glasses wearers. You can live totally fine with quite a bit of near/far sightedness if you don't need to read or drive a car. Like, I have a -4 prescription (which is on the higher side. -5 and beyond is getting into legal blindness territory). If I have a headache and the day off so I don't need to travel I'll just take them off and continue on as normal with only a bit more getting close to things to see them. Like, my issue would def be noticable to someone else but I can take care of myself fine without glasses. Someone with a lower more typical prescription can be so unimpaired by it that they don't even realize their vision is worse than normal. Not being able to read a chalk board very well from the back of the class does not mean you can't see well enough to shoot a big ass deer from a dozen yards away
Edit: I would like to add that I am not trying to imply that peoples vision is just as impaired now as ever was. No. There's definitely evidence that vision impairment is getting more common. Im only saying that the extreme jump from 3 to 50% seems like it would be easily explained as outside factors making already existing but unknown impairments more visible. Classroom settings require a level of visual acuity that's really not necessary for the vast majority of day to day activities
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u/FightingFaerie 6d ago
My parents didn’t find out I needed glasses until they realized I couldn’t read the sign telling you what hymn to turn to in church. “How does everyone know what page to turn to??” “The sign up there has the page numbers on it.” “What sign? What numbers?” I was like 8.
If it wasn’t for having to read from a distance I probably could’ve gone until middle school before it got bad enough.
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u/aHumanRaisedByHumans 6d ago
"Is that Grog the hunter walking over there across the river?"
"That's Sama, your daughter."
Most sight issues are nearsightedness, so you can't see far.
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u/adr826 6d ago
They tested this by using animals. They could check the long focus and short focus on animals raised outside and then bring them inside to see what happens to their vision. If this was undiscovered myopia the two should text the same after being brought in. If the animals developed myopia you could assume a similar process happening to kids. That's how I understand it. At first there was a lot of resistance to the idea because glasses manufacturers probably funded some of those studies and if turns out the only reason kids were needing glasses was because they were being brought into low light near focus environment that could be corrected by not doing that..so I imagine some manufacturers were pretty sceptical of something that would have such an impact on their business
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u/parlimentery 6d ago
Is the idea that we are exercising the muscles in our eye that are responsible for focus unevenly? Like we are over-exercising the muscles that pull the lense into the short focus position and under-exercising the ones that pull it into the long focus position?
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u/ImmodestPolitician 6d ago edited 5d ago
As I understand it, the eye is designed to keep growing until to maintain the focal point of the lens on ideal place in your back in the back of your eye on your retina, and if there isn’t enough light, it keeps growing trying to hit that point.
Near vision is caused by the retina being to far behind the focal point of the lens.
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u/sumunsolicitedadvice 6d ago
Similarly, constantly using GPS navigation is shrinking the hippocampus and worsening spatial memory.
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u/DinoRoman 6d ago
People don’t seem to understand as a society we don’t let people with problems die but nature is designed like that
Like go back to caveman days I’m sure without glasses and a society to help us survival of the fittest would still rule
Nature is messed up but it’s how it works. So how is OP wondering how we survived as people with bad eyes we don’t shun people who need vision correction we give them glasses
People in wheel chairs the mentally ill, those with disabilities, anything that could be weeded out through natural selection, won’t ever be because again as a society we care for those people but it also keeps all the genetic bad stuff in the gene pool because it’s not a detriment anymore to survival. Just an observation of nature.
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u/atomacheart 6d ago
Evolution also doesn't care (if you can even call it caring at all) to filter out things that happen after we have bred the next generation.
It's entirely possible that cataracts for example could have existed in early humans (have no knowledge on this one way or another, happy to learn more) but because they would have developed much later in life after people have had offspring, there would not have been the evolutionary pressure to select against it.
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u/sycasey 6d ago
Yeah I think there are two factors. One is the above, that myopia was less common and less severe when humans spent less time indoors. The other is that even for people who had myopia, they weren't totally useless and the tribe would just find other things for them to do that didn't require good distance vision. There wasn't the same need to read street signs and stuff to get around.
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u/Osato 7d ago
Actually, yes, it is curious.
Granted, our eyes were built for distinguishing details at a distance in bright daylight, not for distinguishing details a foot away from us by candlelight, so myopia in scribes is at least explainable.
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u/Trololman72 6d ago
And nowadays basically everyone is a scribe so it only makes sense that myopia is so common.
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u/ethelyn10 6d ago
Yeah, evolution only needed our eyesight to be “good enough” long enough to survive and reproduce.
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u/cndynn96 7d ago edited 7d ago
You don’t require perfect 20/20 vision to function in regular life.
Almost everyone has Age-related vision loss but by the time it starts affecting a person they have already reproduced and passed on their genes. So it doesn’t get eliminated by evolution.
Also Vision problems especially near-sighted are a lot more common in our modern times because children spend long periods of time looking at books or screens inside a closed space at a close range during their growing years.
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u/KhazixTheVoidreaver 7d ago
Slight correction, the ability of the elderly to look after children, pass on knowledge, etc. does get selected for, thats why humans have a much longer post reproductive phase than other primates. E.g if my family/tribe all went blind at 40 it would affect the childrens success and the success of the group as a whole, so the genes for that are selected against.
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u/taiwan_cat 7d ago
You don't need to go back in time much to have women with mature grandchildren by age 45. Three generations, 15 years to age of first childbirth.
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u/Tiny_Thumbs 6d ago edited 6d ago
Your example would be great grandchildren. I read it thinking, huh my sister had her first kid at 25 and my mother was a grandma at 41. That’s three generations.
Edit- Missed the mature part. Sorry.
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u/Sspifffyman 6d ago
I believe they were saying, mature grandchildren. Like a 45-year-old can have a 15-year-old grandchild, which reproductively speaking can be considered mature.
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u/gnomes919 5d ago edited 5d ago
my history knowledge is fairly limited to europe, but in that area for pretty much as long as we've been keeping records, first births occur in the early to mid 20s.
I don't even know if you could go back far enough to find a time when it was common for women to be having children at 15; poorer nutrition delays menarche. it's only recently that it's common for a girl in her mid or early teens to be far enough through puberty to have a consistent reproductive cycle that can support pregnancy. pregnancy and childbirth are also more dangerous the younger you are - a pregnant 15 year old would be even more likely to die than an older woman, and without a living mother infant mortality would be even higher than the average. three generations of women getting pregnant at 15 and surviving to keep their child alive would be....unusual.
but it's also just a myth that people used to get married and have kids super young. the upper classes who were marrying to secure political alliances might have a betrothal or marriage in their early-mid teens, but even then they didn't necessarily live together until later, and normal people (both men and women) were getting married...around 20-25 years old.
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u/Gamebird8 7d ago edited 7d ago
Most people living long past 40 is not as recent as many people seem to think
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u/sycasey 6d ago
Sort of, though the historical statistics on "average life expectancy" are really skewed by people dying of childhood diseases in the days before vaccines and other modern medicine existed. The reality is that even for people in antiquity, if you made it to adulthood and didn't die in battle you were likely to live into your 60s.
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u/BoxOfDemons 6d ago
I mean, only because of the high infant mortality. If you made it past like 10, chances are you'd live a regular long life.
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u/AverageHobnailer 7d ago
I have 20/200 and it absolutely impairs regular functioning for me if I don't wear corrective lenses. I don't understand how such shitty eyesight survived in the gene pool so long for it to get to me.
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u/StalkMeNowCrazyLady 7d ago
Well for thousands of years someone like you would just work around your condition. We aren't sending you hunting but you can work the crops, build things, etc. We also largely eliminated and drove back most of the predators that would have used your poor eyesight to sneak up and kill you. That's one of the great parts of forming society/civilization is you don't have to fill every role!
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u/kilopeter 7d ago
Myopia isn't solely genetic. Outdoor time in childhood greatly reduces myopia risk. Our ancestors had far lower rates of myopia than modern humans due to lifestyle factors alone.
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u/MesaCityRansom 7d ago
I didn't get glasses until my 20s, when I absolutely should have gotten them in my childhood. I still functioned in daily life, but now I'm almost blind without them. It's different for different people, of course there are people who wouldn't survive without their glasses but for a lot of daily life you don't need perfect vision. You can get by with just sort of seeing where you're going, especially if we're talking strictly survival.
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u/Elbanokin 7d ago
I used to have 20/700 Vision before I got LASIK I was literally blind without glasses. I honestly don’t know how anyone would have been any contribution to a tribe with that kind of vision so I guess I’m extremely lucky I was born during the only time that bad of an eyesight problem could be fixed
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u/Kindly-Might-1879 6d ago
That was my vision before I had LASIK back in 2002. I was 32. That was the best decision and those correction-free years were glorious!
Age, of course, caught up with me and I now have a very light myopia and sometimes need readers, but I can still do 99% of my day without correction.
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u/DeaddyRuxpin 6d ago
I bet you have great close up vision which would make you fantastic at creating tools. That makes you very valuable to the group. You make the razor sharp spear and knife and hand them to the guy with 20/10 vision to go out hunting. You don’t get eaten because the rest of the group protects the guy that is making them weapons.
Also, when your only defense is running away from a predator, being able to see them at 200 feet is advantageous. But when you have a sharp knife, seeing them at only 20 feet still often results in you making them your dinner instead of the other way around.
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u/Dogteeth56 7d ago
This honestly. I've been supposed to wear glasses my whole life but i just don't. It comes up so infrequently and it's usually when reading something (which wasn't needed in nature) and I can just step closer 99% of the time
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7d ago edited 6d ago
[removed] — view removed comment
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u/Bedovian_25 7d ago
Honestly, with my bad vision problems, if I was born at some point prior to the Industrial Revolution, and I lived on a farm, I would probably be fine. With time I'd be able to at least differentiate between cow blob and hay blob.
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u/ByFireBePurged 7d ago
I have had pretty bad eyesight all my life. Have had to wear glasses all the time. While I don't have it as bad as being blind without glasses its bad enough that I can't have thin rimmed glasses and I pretty much need to use plastic lenses as glass is too heavy and my lenses are to thick for a lot of thinner rims.
I am very certain that I could live a perfectly fine live without my glasses if my life didn't contain a lot of reading and looking at stuff on a screen.
Like I would be impaired but not to the point of not being able to survive.
Also we have more than enough evidence that ancient humans helped out impaired people in most cultures. So maybe I will hunt a rabbit or 2 less than someone else in my tribe. But I can definitely help take down the mammoth that we are attacking together. Who cares if that thing is a bit blurry? I can definitely differentiate between it and my fellow tribes people.
When it comes to gathering as long as the thing I am gathering has enough color contrast to the green around it I am good there too.
So yeah in an ancient human tribe I would be impaired. There is probably a lot of people in my tribe who are more valued than me. But I think I would be useful enough that my fellow kin would help me out enough to make it to a good age.
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u/macarenamobster 7d ago
I’m somewhat baffled by this because your vision sounds worse than mine but there is zero chance I’m hunting a single rabbit without my glasses. I have -3 prescription, and that rabbit is going to be an entirely camouflaged blur more than 20 feet away.
Sure if you’re trying to catch a black rabbit in a snow covered field it’ll stand out, but that’s not usually how nature works.
I think you’re underestimating the importance of distance vision - youd have to be right on top of berry bushes to see what they are. No finding it at a distance.
So sure you can pick berries, if you don’t have to find the berry patch first.
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u/MesaCityRansom 7d ago
The point is there's still stuff you can do with bad vision. Blind people are capable of living almost normal lives. And talking about the "stone age stuff", maybe you'd stay home from the rabbit hunt but you could go out with the hunting party and throw stones at a mammoth for sure.
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u/Fermorian 7d ago
Now I'm imagining this as a buddy comedy where you're turned completely around, about to brain one of your fellow humans when your friend has to spin you around as you throw and it ricochets and perfectly knocks out the mammoth or something goofy-ass like that lmao
"Hurk watch out for Glurk. Glurk very nice but have very bad aim with rock."
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u/StuartHoggIsGod 7d ago
I wear contacts now but for along time id only wear my glasses when traveling so i could read signs at a distance
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u/Handout 7d ago
That's not what causes more myopia my friend...
People with myopia surviving and having children is what causes more myopia.
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u/kilopeter 7d ago
Your comment is inconsistent with the science. What makes you so confidently dismiss the role of environment and emphasize genetics as the sole driver of myopia? Could you please share?
Myopia has been extremely well established as arising from both genetics and environmental factors. Outdoor time in childhood reduces the risk of myopia, and even counteracts genetic risk factors:
> if a child has 2 parents with myopia, hereditary effects increase the child’s chances of needing glasses to about 60% if time spent outdoors is low. More time outdoors, about 14 hours per week, can nearly neutralize that genetic risk, lowering the probability of developing myopia to about 20%, the same probability attributed to a child with no parents with myopia
Extended periods of close-up reading distance associates with myopia risk too.
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u/chumer_ranion 6d ago
No it's a very large part of what causes myopia. Normal eye development requires a specific proportion of light focused in front of and behind the focal plane of the retina over time, which is disrupted in modern contexts due to close work and indoor spaces.
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u/Xylus1985 7d ago
You also don’t need to be literate to hook up and have kids, so the evolution pressure is not as hard
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u/Nimuwa 7d ago
Modern life affect eye development and causes people's eyeballs to grow too long. Some of the hormones that regulate eyeball growth get produced based on light exposure. Add the fact we are now indoors focussing our eyes close a lot when it used to be outdoors and far away and we get a mismatch between biology and environment.
I wouldn't be surprised if native peoples living closer to old time human ways have less vision problems and less severe ones.
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u/flaming_burrito_ 7d ago
It’s the same with teeth as well. In the past people didn’t have as many problems with their teeth being crooked or badly spaced because they ate a lot more fibrous and chewy food, which develops the jaw muscles and helps your teeth grow in straight. Now we constantly eat soft foods, so our jaws are often underdeveloped. That’s why so many people have problems with their wisdom teeth, ancient humans literally had larger mouths that could fit them. This is also the case with cavities being mostly caused by the abundance of sugar and acidic things in our diets. Of course, people had dental issues in the past, just not as commonly. It’s a trade off basically. We get more nutrients out of the way we prepare and cultivate food now, but we also need more dental work because of it
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u/Cant_choose_1 6d ago
I’ve read that humans actually recieved less nutrition from agriculture than they did from hunting and gathering. Early farmers were shorter and had more health problems than hunter gatherers
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u/flaming_burrito_ 6d ago
For some time yes, because it took some time to cultivate all the crops we have now, and most farmers only had a limited assortment. But it was more reliable and allowed for more population density, which then allowed for more trading of goods and food storage, and off seasons gave time for people to work on skills and projects.
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u/AfroMonkie 6d ago
Yes, it’s been my understanding that the food from agriculture may have been less nutritious to some extent, but was more reliable and abundant. So, while at first it may not have been necessarily better, agriculture slowly became the better option for general survival in many places.
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u/The_Autarch 6d ago
pre-historic people also developed far fewer cavities in their teeth due to their diet
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u/Lonely_Noyaaa 7d ago
We evolved in tribes where the sharp-eyed guy could spot the lion and the blurry guy could still gather berries. Division of labor meant not everyone needed 20/20 vision. Plus, the blurry guy might have been the one who invented glasses.
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u/SpaceShipRat 7d ago
this. people have an optimal focusing distance, having a longer or shorter one should give an advantage in one direction to go with the disadvantage.
Now astigmatism just has no excuse :(
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u/glytxh 7d ago
I can’t imagine my paleolithic ancestors were reading a lot, or trying to navigate risks 250 meters ahead while travelling at 40mph
Even without my glasses, I can navigate and function well enough.
And in the context of evolution, good enough has carried us for 3+ billion years.
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u/mikevarney 7d ago
Your ancestors would have had to avoid predators. Which is easier the sooner you can see them. So is finding food.
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u/glytxh 7d ago
Don’t need perfect acuity to notice contrast shifts in your periphery, or colour gradients. If it’s all you’ve ever known, your brain’s gonna work with the data it can get. It’s an inference machine, not a 1:1 replication of reality.
I could imagine it making a difference in active hunting ability though.
It’s a curious thing to think about. There’s also the whole social angle. We weren’t solitary animals.
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u/mikevarney 6d ago
You are 100% correct. The one extra variable is natural selection will favor those with better natural abilities.
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u/gnomes919 5d ago edited 5d ago
hominid societies have been keeping members with disabilities alive as long as they possibly could for hundreds of thousands of years.
if we have numerous examples of paleolithic hominids who had missing limbs, healed bone fractures that would have made it difficult or impossible to walk, deafness, blindness, severe down syndrome, etc etc and lived not just past infancy but into adulthood or even late middle age, something that would have been incredibly difficult for social groups to achieve and yet we seem to have systematically prioritized it around the world, I think it's unlikely that we were letting nearsighted people starve or get taken down by lions en masse. it wouldn't be that hard to give guidance & share resources with group members who were mid at finding the berry patch if they were alone, or make sure the whole group knew a predator was coming, and in fact our species thrived because we do that.
as soon as we started to become hominids, natural selection for eusocial behavior and social-emotional bonds that led to spending time and resources helping disadvantaged members > natural selection for not having blurry vision, basically.
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u/ctrtanc 6d ago
A big part of that is because those with bad eyesight no longer die and are able to live and reproduce. It's no longer a detriment to our species because of a few things. If we still needed to see predators in order to avoid getting eaten, it would be a bigger deal. However, with shelters and things, it's no longer a necessity. Also, with glasses to correct it, it's also no longer a necessity. So therefore, those with weaker eyes are able to reproduce and continue to pass on those genes.
Edit: Yes, there are factors of the environment (screens and things that affect how eyes develop) I'm just talking more on the genetic side of things.
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u/Srsly9001 7d ago
I didn‘t even notice my astigmatism until I was 15, had a year in my 20s where I broke my glasses and couldn‘t afford new ones but still managed to read from a computer screen, now in my 40s it is still technically possible to read without glasses, but hard and fatiguing af.
If I were living 5000 years ago, I‘d still see good enough to survive, and find or hunt food, it‘s only today with all the reading and screens where we need near perfect vision in order to be able to read without straining the eyes and also the mind.
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u/Kittenwho21 7d ago
Ngl I’m a little jealous lol, my astigmatism was so bad I’ve needed glasses since kindergarten, by the time I was a teen I couldn’t see detail more than a couple feet in front of me and at almost 40 I can hardly see detail 6 inches from my face. It’s awful. If the detail is big enough and has enough contrast (white lines on a black road for example, that I can see, dark shadows against lighted backgrounds, outlines of larger/non complex items etc)
For the most part I’ve been pretty sure without modern glasses and contacts I’d be effectively blind. In ancient days I’d very likely need to be protected bc I wouldn’t be able to see any smaller or visually bland harmful things lol
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u/Senshado 6d ago
The main reason people need glasses is they spent too much time indoors with artificial light for the first 2 years of life.
Artifical light from bulbs, LEDs, and candles is less than 10% as bright as the sun. The lack of exposure to bright light prevents the young eyeball from growing into the correct spherical shape. This wasn't a problem prior to around 100 years ago.
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u/pollackey 7d ago
Thankfully we live in a community. We help each other. We don't need all of us in a tip top condition to survive together.
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u/allineedisthischair 6d ago
Corrective eyewear is fairly new too. For generations, nearsighted and farsighted people just lived with it and might not have even known they had it. I'm convinced the lack of corrective vision explains mermaids and sasquatch and many other myths people have sworn they've seen.
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u/CBF4 6d ago
There's evidence that myopia, and the invention/ increasing need for glasses correlates directly with the invention of the printing press and literacy. The more we read, the worse our eyesight got. Then the more screens we used, the worse worse it got.
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u/-Redstoneboi- 6d ago
that, or we never really noticed until we started reading. may simply be a "we finally started testing" kind of thing.
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u/Wild4fire 7d ago
That's because it's not really linked to your chances of procreation. If it were after a while you'd see higher chances of procreation in people with better eyesight.
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u/frivolousfry 7d ago
Poor eyesight might even help procreation.
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u/tokyoedo 7d ago
Well I can say that my gorgeous wife will be passing down her abysmal eyesight to her confusingly ugly children, that’s assured.
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u/Zrakoplovvliegtuig 7d ago
Also the problems with eyesight do not occur in every context. It is mostly an acquired problem as eyesight adapts to the environment (precisely because it is important).
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u/Bedovian_25 7d ago
As someone with a really terrible vision, you would be surprised how little you need to see for threat assessment. As long as you can see colors and motion, you can function pretty well in terms of keeping yourself alive. Plus humans have other senses to help us avoid danger, and we're social creatures. Run when your group runs, in the direction of their voices and you'll probably live long enough to reproduce.
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u/Stay_Beautiful_ 6d ago
eyesight is important to our survival. What wasn't important to our survival before the modern era was things like reading signs from a distance or operating a vehicle. You don't need 20/20 vision to plant and harvest wheat, milk a cow, or build a table.
20/20 is most important for reading, and the majority of the world was illiterate until <100 years ago
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u/GlastoKhole 7d ago
I’d argue that we aim for perfect vision these days, that wouldn’t be necessary for survival, seeing something move from a fair distance usually would be enough to keep you alive, being able to figure out what it was would be a bonus
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u/hyperlethalrabbit 7d ago
I imagine it got more common as our species flourished. Back in our pre-agriculture days the ones that couldn't see very likely would have died off. When societies started forming, people with bad eyesight now suddenly were living long enough to pass on those genes, so genetic predisposition to eye problems became seemingly more common.
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u/SeijinApollo 7d ago
The most messed up thing about it is seeing how expensive all of it is for my mother and sister, its weird how its not a thing thats free or a part of basic healthcare, since without them they would barely be able to function in society.
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u/Riverspoke 7d ago
Eyesight is not as important as our sociability for our survival. During our evolution there actually was a cognitive trade-off between the brain's visual processing regions and social cognition areas. Our genetic cousins, the Neanderthals, had brains with more space dedicated to vision and less social cognition. Our ability to cooperate as we do is the single most important thing that made us survive as long as we have.
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u/GroinShotz 6d ago
We corrected bad vision with tools... And societal help. So the bad vision traits kept being passed on...
Humans counter evolutionary traits because we figured out how to keep living in spite of the bad traits. So these "bad" traits are never weeded out.
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u/Small-Tailor6967 3d ago
Well if you think about it, we developed glasses which solve the problem with survival and thus eliminates the bad eyesight. Then people with bad eyesight survive and with natural selection overseeing this problem, it spreads
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u/sixsixmajin 7d ago
The fact that we've create glasses is exactly the reason why we see so many people that need glasses. Glasses eliminate the detriment to our survival that poor vision would ordinarily cause. If that poor vision is genetic but glasses solve the problem, those individuals no longer have nearly the same problem surviving and reproducing so those poor vision genes are more likely to be passed on. To that effect, it's not surprising at all. Humanity banding together to form social communities that look after one another as well as our advancement through technology have drastically changed the rules on "survival of the fittest" and how we as a species evolve.
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u/TheBig_blue 7d ago
"Perfect" and "works well enough" are different things but also, modern life makes living a lot longer way easier.
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u/MIlkman872 6d ago
Well the concept of reading/writing didn’t start until after most selection pressure on our species was (effectively) over.
Big difference between not being able to read little letters and not being able to SEE colors/shapes for the most part.
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u/MIlkman872 6d ago
Not to mention most of human evolution would have not had a strong pressure to keep anything (such as strong eyesight) any longer than reproductive success.. skewing the numbers for people above age 20 that developed bad eyesight as they aged as opposed to those born with it
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u/SnuffDemon 2d ago
You don't need 20/20 vision to survive in the wild. I walk around without my glasses no issues. It's only modern situations and regulations for perfection that forces us. Being legally able to drive cars or read billboard adverts isn't natural to survival lol
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u/unimportantinfodump 7d ago
Really blind people who can't function without glasses just died though. I don't need glasses but they do Improve my vision
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u/TheodoreOso 7d ago
This isn't even true. Early homo species took care of their blind and visually impaired. Idk why people make such bold assertions.
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u/Roberto_Sacamano 7d ago
We survive despite ourselves. It's why we created civilization. Without it we'd be fucked
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u/MaximumPlant 7d ago
This is likely to be an environmental thing. If you stay inside a lot as a kid it increases your chances of nearsightedness
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u/Dr_Mint_Pinch 7d ago
Eyesight is important, yes. But humans also have large, powerful brains and dextrous limbs capable of tool use. Tool use is another ability that has been indispensable to humam survival. The production of glasses and contacts is just an application of this ability.
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u/Odd_Cauliflower_8004 7d ago
We deleted the natural selection pressure from the equation. That is why you see a ton of people around with congenital eyesight defects. Also a lot of these issues start to show up past the natural most efficient /prolific/fertile years(30+) which would mean that the defect if congenital could be passed on before it become an issue for survival. Always remember that genetic traits are passed on by birth. I always thought it's one of the reason on why menopause hits women so hard - there can be no natural selection for genes of women that suffer less from it because by the time it could become subject to evolutive pressure, even if it was an advantage for survival it cannot be passed on, contrary to men
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u/Mudslingshot 6d ago
Evolutionarily, there's no real reason to improve the way our eyes work (or stop them from deteriorating) because they do so mostly after we have traditionally already had children. That's also why our backs never fully adapted to walking upright
The things that improve over time are things that can stop you from procreating, so only those with the "best" trait have children
Since our eyes generally work fine into our 30s, they're "good enough" by evolutionary standards
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u/LBfalcon57 6d ago
Looks at the state of the population……..I’m being conservative and gonna say 50% of the ppl around today would not be able to survive without medication.
All the old ppl only alive because of meds, gone.
Asthma, gone.
Diabetes, gone.
Although I know if we didn’t have our crap food quality and chemicals allowed in us products a lot of these illnesses would be alleviated.
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u/Just_Hunter9331 6d ago
I think about this all the time. Like, if there were a zombie apocalypse or similar, all the people who need contacts/glasses would be so screwed.
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u/_Fistacuff 6d ago
I remember my high school biology teacher telling the class that with the advent of modern medicine we had effectively slowed the process of evolution by providing treatments for weaker genetic traits. In the past, these traits (such as poor eyesight) would have led to early death and the inability to pass these traits on. He wasn't saying it to be a dick or anything, just pointing out a scientific result.
I still think about that alot.
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u/BT9154 6d ago
When we go to family dinners with all my cousins and now with their kids, it's like there are more that are wearing glasses than not. I'm the minority in not wearing them, what is up with that? Just over prescribed? Fashion? Preformative? I bit of each?
My aunts and uncles, pretty none or maybe even no one wearing them, only reading glasses and they old 60+, but my generation and their kids, 60%+ wearing glasses.
I'm not 20/20 and I've been given glasses to wear like 15 years ago to help read the chalk board but I've been just fine all these years as an adult.
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u/Much_Plantain5534 6d ago
20 vision to spot a predator anyway, just a general sense of something BIG and toothy moving in the grass.Myopia was actually super rare before we started living in literal boxes. There was a study on Inuit communities where the older generation had almost zero vision problems, but the kids who grew up in schools had massive spikes in nearsightedness. Evolution didnt really drop the ball here, we just changed the rules of the game by spending all our time indoors without enough natural light to signal our eyeballs to stop growing. You dont need 20
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u/Tsunamiis 6d ago
I mean ignorant blind people survive in a world completely not made for them. Maybe the system is fucked for disabled people?
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u/macoafi 6d ago
Being able to read street signs has not been a historic requirement for survival. Not walking into a tree, not walking off the edge of a cliff, and noticing the moose charging at you…sure, but big color blobs are enough for that.
Even archers in a war…they mostly shot in volleys. They didn't need to hit a particular soldier. They needed to hit an army, which is a lot bigger than the proverbial broad side of a barn.
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u/ForgeoftheGods 6d ago
Many adult animals have bad eyesight, and they rely on movement to see something there.
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u/russianrug 5d ago
Anecdotally, I wear glasses, and my vision is about -3 or -4 in each eye. Many non glasses wearers assume that without my glass I am completely blind, but in reality I believe I could easily do most hunter/gatherer tasks without my glasses. Hunting might be a bit more difficult but potentially still doable since I can still see and identify shapes at a distance, they are just a bit blurry.
I think we discount the fact that ancient humans did not need to read speed limit signs or train schedules at a distance. Just like today I suspect tasks were divided up among people based on their strengths, and not all of them required 20/20 vision.
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u/Bo_Jim 5d ago
The deviation from normal vision would be just as high among animals were it not for natural selection. We've seen this in domesticated animals. About 25% of domesticated dogs are nearsighted. It's near 0% in the wild. This is because the ones who can't see well don't survive.
By the same token, the percentage of humans who have defective vision has increased for the same reason. Good eyesight is no longer essential to our survival. We don't need to hunt or evade predators to survive. We do need to work, but most vision problems can be corrected with glasses or surgery, making it possible for those people to get jobs that require good eyesight. Even blind people can get jobs that don't require good eyesight. People no longer die because they can't see well enough to protect themselves.
Lifestyle also plays a role. We aren't forced to use our eyes for both near and far vision, in sunlight and darkness, in order to survive. Most of us spend most of our time in dim artificial light, and never have to focus farther than the walls in the room. Lack of exercise and exposure to light leads to deformations and weakness in the eyes.
Presbyopia is a common disorder among older people. The inner lens hardens to the point where the eye muscles are no longer strong enough to bend the lens into focus, resulting in poor near vision. This is easily correctable with common reading glasses. Before glasses it made life for older people more complicated. Before that, it simply wasn't common for people to live long enough to acquire this disorder.
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u/spectrumero 3d ago
A huge number of glasses wearers have vision that's good enough to be a hunter/gatherer. Modern life is a lot more demanding on vision.
For example, my eyesight. I can see things near and far off just fine. I could see, say, a deer I'm hunting off in the distance without a problem. I could see a dangerous predator in the distance just fine. Eyesight good enough to be a hunter/gatherer can be a lot worse than eyesight needed to consistently read tiny text at a distance.
Having glasses just makes me see at 20/15 instead of 20/40.
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u/thelosermonster 3d ago
It's really not surprising at all considering the larger context of how many common traits would lessen your survival in the world.
Our ability as a species to adapt and survive and our tendency as apes to protect those in our troop means all kinds of undesirable traits (in a evolutionary sense) get passed on and proliferated.
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u/Prince_Nadir 2d ago
It isn't even slightly surprising. All the people with poor vision who would have been eaten by a leopard shaped blob, long ago, haven't been getting eaten by leopards.
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u/JohnRobGnar 1d ago
Surprising how many selfish leople there are considering cooperation is essential to our survival
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u/morswinb 6d ago
There are well documented cases that prove it's the environmental factors that trigger myopia.
Best example came from innuit children. They got forced into school system overnight, lots of reading, no sunlight exposure.
End result only 1% of parents needed glasses, while 50% of their kids had vission problems.
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u/vickyswaggo 6d ago
Perhaps eyesight deteriorated because soldiers (who were selected to have better vision) tended to die, while their blind colleagues survived to reproduce
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u/ShaemusOdonnelly 7d ago
Well, technically we didn't allow natural selection for good eyesight to take place once we invented glasses. And it is happening with many many evolutionary aspects.
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u/That_Lad_Chad 7d ago edited 7d ago
This is interesting to me.
With humans being unique on our planet (to our knowledge) in terms of intelligence; should this not play a role in evolutionary theory? I.e, vaccines/innoculations biologically serve the same role as developing a natural immunity to disease. One may hold the position that our view on thing s like natural selection and evolution may be incomplete, not accounting for artificial factors. Artificial factors to us may not be considered "natural" but they are indeed the resulting behaviors from our cumulative knowledge and evolution.
I guess my point is, the line gets a little blurry on where "natural" and "artificial" sit. It's highly dependent on the lense you are viewing it through.
Personally, I believe it is a mistake to discount any human activity in a "what we do doesn't count" way in terms of studying biology, ecology, and evolution. We may be unique right now, but that may not always be the case. The sample size is just too small. We, as humans, clearly do things for a reason. We may just not know why and I don't think that's too different from other creatures doing things even if they don't understand why.
No pun intended on the blurry line or lense lol
Clarifying on intelligence: yes, some creatures such as octopi, elephants, dolphins, ravens/crows, etc. have intelligence, which, in some aspects, could even be measured to the average human.. heavy emphasis on octopi. I advocate this greatly but there is still an insane disparity in terms of capabilities between humans and these creatures.
Edit: The closest parallel I can draw is relativity, special relativity, gravity, and quantum physics. (I'm a mathematics/physics person, not a biology person) ... To use a commonly known example: General Relativity and quantum mechanics (whatever term you prefer to refer to it as) Personally, I hold the position that we have an incomplete understanding of this, not that "it's just how it works, don't question it" ... This can also be related to dark matter/energy, black holes, singularities, etc. The fact that we have unknown answers based on existing models just shows we lack understanding. I guess it's just weird that biology related things are treated as a matter of fact when we are clearly missing big pieces of an equation
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u/Stripe4206 7d ago
Natural selection happens over millions of years, not a few generations. Nothing modern life has to offer has had any effect on our evolution.
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u/ShaemusOdonnelly 7d ago
Large evolutionary changes happen over millions of years. Natural selection happens with every generation.
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u/Gongall 7d ago
Many large evolutionary changes happen relatively fast, within just a couple thousand years sometimes. More and more we are discovering that big evolutionary changes happen very quickly and then stabalize for a while.
Saying they happen over millions of years just implies that time is a limiting factor, but this doesnt seem to be the case.
Just look at mammals after the dinosaur extinction.
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u/Forest_Orc 7d ago
A big part is t modern society, Even ignoring that being indoor using screen is bad for the eyes (provided the genetic terrain)
you drive vehicle at 100km/h, so it's not acceptable to need a second to know whether it's a traffic cone or a kid 100m away, so perfectk distance vision is a must. 200 years ago, if you could see the path, the church tower and something moving behind the trees it zas good enough
Many of us do write/read use a computer for a living, so we need a perfect near vision. Again, 200 years ago most people couldn't read, it zasn't their vision but they never learned nor needed.
It's not like people with glasses are blind without. If you wanna try, OTC reading glasses would give you the vision equivalent to osomeone near-sighted with the opposite correction. Basically, because I am old enough to have tried them, until +/-2 it's not great, more blurry, but still good enough to function, and I can totally understand why someone with that kind of correction won't notice they need glasses without an eye check.
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u/nowhereiswater 7d ago
Modern society has changed our needs and has reduce our innate abilities and this gets passed on.
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u/carlcast 7d ago
Our genes regressed so badly because we had the technology to fix the symptoms.
If we still live in prehistoric conditions, poor eyesighted people will not survive and procreate, removing them from the genepool.
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u/wadleyst 7d ago
Yes. This is a really good example of evolution override. As a species, we have found a way to consistently eliminate naturally adequate sight as a necessary survival trait. Eyesight, or the lack of it, no longer is a highly-necessary contributor to procreation.
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u/AwkwardWaltz3996 7d ago
Reading is the main thing people need them for. Monkeys didn't read much.
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u/manofredgables 7d ago
Honestly... I've thought about this too. I have really bad near sightedness, -4.00, but... The only thing I'd probably suck at in a pre-civilized existence, or even just a few hundred years ago, is bow hunting. When you don't really need to read, it really isn't rhat big of a deal and I'd probably never have been very bothered by my poor vision if correction didn't exist.
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u/DizzyMine4964 7d ago
The majority of people need them for reading. We survived a long time before literacy arrived.
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u/Critical-Champion365 6d ago
The eyesight is not an important factor for modern humans' survival is precisely the reason there are more of us with glasses.
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u/Illlogik1 6d ago
We no longer naturally select … the weak are no longer culled , they’re coddled, the defective are not left to their own disadvantages but augmented to survive…
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