Some of the information in this video is incorrect. 1. The majority of the refracting power of the eye is from the cornea, approximately 45 diopters worth while the lens is only approximately 15 diopters worth. 2. We don't "squeeze and pull" the lens. The lens has a certain shape that it "wants" to be in, or it's relaxed position, that which allows us to see farther objects and it is the more rounded shape. When we focus with the lens to see objects up close to us, the ciliary muscle pulls the lens to flatten it. 3. Astigmatism is not caused by the cornea being too round. Instead it's because the cornea has different refracting powers in different meridians. For example, the cornea may have a different refracting power at the up/down meridian versus the left/right meridian. A lot of people are worried by the diagnosis of astigmatism. But in reality the majority of people have at least some astigmatism, something like >80% of people. My source? I am an eye doctor...
+Andreas Tollånes (FanzyPantz) They need opposable things and the knowledge on how to forge glass into shaped with different focal lengths. Which I doubt animals like rabbits or frogs can xD
That, and they probably just get used to their eyesight that correction would be too strange and possibly deadly for them if they couldn't learn to adapt to it.
When I saw this video I was thinking about when I tried putting my glasses on one of my pet bunnies, and they knock it off. And yes, I need my glasses to see words from far away(I can see fine without glasses, but they help me see more specific details). Guess my bunnies hate glasses XD
+Setillos how much does it take to see a hole big enough for you to fall in or a tree big enough for you to run in. you can be practically blind and still be able to.
+Dotz yeah, unless you are distracted by upcoming death and/or have narrowed vision like such animals and you can see mostly only central part of what's in front if you. Also, that hole/tree doesn't need to be big. Hole needs to be big enough to make you lose your balance so it doesn't need to be that big and tree just has to be big enough for you to trip over it.
Most canine species have pretty bad eye sights compared to us humans in general. They have their other senses as compensation. We humans are heavily focused on our eyes as main medium of information around us.
I'm SO glad you brought up the "time outside" reason! When I first read about that, I was super excited, because it's yet another reason for what I do.
Eyes are the one thing I am ridiculously squeamish about. I can't handle looking or even thinking about things touching my eyes. I have to turn away every time my sisters put their contacts in. All that to say, that sudden close up of someone putting their contacts in made me almost fall out of my chair. Edit: Oh yeah, the video was great too. :P
I am the same way. I don't really like having glasses, but I use them because the thought of touching my eyes to put contacts in kills me. My greatest fear is getting a needle in the eye....
same except something about the eyes bother me i cant resist but put my hands near my eyes once i saw a video where a cat scratches a girls eye after that i felt like fainting
I have had my natural lense removed beacuse of injury, and have been confused for ages on why I have hade been able to see in rooms lit with a blacklight, as they were lit by a normal violet light. The final part of the video explained a long time cofusion in my life! Thanks dude!! :D
Great video! You hit so many great points! Just a quick clarification (with recap). Refractive error (myopia or hyperopia) is caused by the axial length of your eye (correct in the video) and the power of your cornea.....only a minor part from your lens. The lens will naturally try to accommodate (flex) to bring objects in focus but some individual's refractive error (hyperopia) is too great for it to overcome. As we get older, we lose the ability to accommodate (presbyopia) and have a higher need for glasses (most of us at near but some for near and far). Since 78% of the refractive power of the eye comes from the cornea, the lens plays a smaller role by fine tuning it. If you have a myopia (near sightedness) it is because your cornea is too powerful or the axial length of the eye too long. The opposite is true for hyperopia (far sightedness). When we perform cataract surgery (replacing the natural lens with an artificial one), the power of the lens doesn't carry much weight in determining the power of the artificial lens. The corneal power and axial length are very important though! In case you're wondering my background, I'm an ophthalmologist and have spent way way too long studying this :) Feel free to see my eye tips at facebook.com/TheEyeMD2016/
Because animals with bad sight, in an environnement where sight is essential, don't survive well. Yup, natural selection ! We, humans and our health care, are (trying to) outsmarting natural selection. Kind of like the Azgards in StarGate.
Because humans are the only animal that's able to work with glass and comprehend how lenses work and how to make them. That's one part of the real answer.
Fun fact - humans can only focus onto the retina in one way. Birds of prey can do it two ways. Meaning they can focus at incredibly high distances for hunting, but also close up, like in their nests.
Joe really reminds me of Chidi from the Good Place in this video. It's mainly the style of shirt and glasses, but also kinda his mannerisms and even face shape
I have kerataconus - where the cornea takes on a more conical shape than a hemispherical one. One of the "treatments" for it is soaking the eye with Vitamin B12 and exposing it to UV light (UV-B I believe), which increases the cross-linking of the collagen in the cornea - though I put "treatment" in quotes because that doesn't actually reverse the condition, it only helps prevent it from getting worse. I've never seen an experiment that specifically checks, but I've suspected for a while that the 'excessive' use of sunglasses during adolescence (when most people start to exhibit the issue) may contribute to the developing of this condition, as it would deprive the eyes of levels of UV that may be required to keep the eye's shape from distorting over time, particularly while the body is going through the changes of puberty. But I'm not a scientist, so, who knows.
I know this is an older video, but I wonder, if adults between 30-40 years old wear sunglasses more often than necessary does that mean that they will have trouble focusing when they're older?
My dog use to wear glasses. As kids we would put our glasses on him and he'd walk around the house. He seemed to like it. He also use to find chewed gum in the garbage and start chewing it. He loved gum and glasses. I miss my dog.
One of my horses needs glasses. He definitely can't see as well as my other horse. My other horse notices things at distance and close up. I think that is why he likes to follow other horses and not lead, plus needs an assist sometimes to find things. Come with me and let me show you where I put the hay out in the yard.
my vision started to go my freshmen year in high school and from when i was a kid till then i was outside every moment i could outside of school. so just going to school takes you out of the sun enough to have that large an effect? but why aren't my eyes getting worse? they've been the same and now i never leave the damn house.
human eyes become rounder over time becoming worse. i got glasses when i was 13 when i couldn't see the chalkboard in school. I'm 19 now don't go outside except when i have to and my eyes are stagnant since when they got bad. Really weird.
Your eyes stop growing at any appreciable rate past your early 20s, and generally have slowed significantly by the late teens. It's possible for your eyes to change after those years (aside from presbyopia which is common past age 50), but generally quite slowly. So sunlight or no your eyes won't change much if you're past your main growth years.
Many people who need glasses around me (me included) have both. I started developing astigmatism after being diagnosed with myopia. I guess it's a common thing
Not at all. We need more of your videos! Daily! My boredom and interest in random science facts must be fed man! EDIT: (For the few of you who didn't know, I was joking. Soo... yeah. xD)
But being a little nearsighted is helpful to literally focus on reading and precision work like soldering. Try taking a photo up close and you will see the image gets blurry
Then there are people who naturally have better vision in general so they are able to do very detailed work and see very far, these people likely just have a better focusing mechanism/better visual system.
Yeah but people who have perfect 20/20 vision could literally do the same thing the human eye is support adjust to see certain things in front of us or a little bit away
I cant believe I'm saying this, I've thought about it, and I thought I never would. The best part about this video, was the sponsor. That site rocks man thanks!
I have very mild nearsightedness but my astigmatism is worse. It gets worse for me after every blow to the head I get (active teen and very unlucky when it comes to cars I’m passengering in). And I’ve not gotten an eye exam since my last concussion. But my glasses still work 90% of the time. My optometrist said it probably gets worse after a blow to the head due to internal pressure changes bulging the lense and it doesn’t fully return to normal. And is why blurry vision is a post concussion symptom
Interesting, right now I'm working on a science video which explains a lot of the mechanisms not quite touched upon here, such as why the lens stops working and what factors including sunlight affect eye growth, and how they make us more near sighted. However, most animals are in fact more nearsighted/have blurrier vision than us so a tight regulated eyeshape is a bit less important. Dogs have 20/75 vision for instance. Only birds have overall better acuity, but that is because they are selected for high resolution vision. Most animals in fact don't rely on vision as their primary sense, and that is why it doesn't matter if their eyesight isn't perfect, which it often isn't anyway ;)
People that use screens can't bend light correctly because they were not told that screens which supply light to the eye are not uniformly lit. This causes the eye to bend and relax thousands of times a second trying to focus slightly in front of the screen and then slightly behind the screen. This bends the lenses just like doing thousands of bicep curls could hurt the arms. the lens get more long (protruding from face basically) and it cannot relax to see far away anymore. Eye strain is pre-myopia. Ben Franklin and Malcom X both read by candlelight and needed glasses. Smart people are smart enough to not need glasses but nobody is ever told the truth because we need stupid workers who blame everything on genetics and these workers cannot question anything.
There's a lot of nearly correct but not quite information in this video. There are two main causes that determine a need for spherical correction which is either the length of the eye as mentioned or the surface radius of curvature. Astigmatism is a non-spherical cornia (so rugby ball shaped 🏉) causing different meridians to have different radius of curvature. If a crystalline lens has to accommodate to focus on an object at 6m or further then you would still need a prescription because the prescription is measured against the unaccommodated eye.
I still don't buy the sunlight thing i think it would be far more likely that the reason is you spend so much time inside sun or not. this would mean that your eyes never have to see far only at most a few feat to the next wall.
it's not sunlight specifically, so much as amount of light total. lots of bright florescent light will tend to cause less issue than inadequate incandescents of lower brightness, for example (though if you're in any way light sensitive, have their own issues. these days you can get LED bulbs though, which are Great for having few or none of the down sides of either.) Bonus points: your eyes make the Exact Same Adjustment to deal with stuff that's really close that they do to deal with low light environments, and the same is true of really bright environments and things which are really far away. So if one causes problems, so does the other. you can get away with looking at stuff up close a lot if you're also in bright light a lot (doesn't have to be at the same time) for example, because the problems comes from your body adopting a natural "rest" position at whatever point you use most, and then it's ability to change that decaying due to what is almost literally a lack of exercise. if you're in dim environments a lot, your eyes will adjust so it's easier to see things from closer in, which will tend to lead to you holding books closer to your face and such, among other things. I actually have the problem. My eyesight is deteriorating quite noticeably because, due to other health issues causing rather crippling head pains with associated light sensitivity (and a problem where my lenses don't focus different Colours properly, and a mental problem which means my brain doesn't filter things enough so more light/sound/etc = bad) i spend a Lot of time in low light environments. My brother, who spends as much if not more time than me in front of computers and the like, but typically has brighter lights where he does so, and spends a lot more time outside (if only travelling too and from the University), has Much better eye sight. meanwhile, from memory, the various groups who live(ed) on the Mongolian steppe, or in other bright, open environments, typically have better vision over all... and when they Do have problems it's most commonly that they can't see things which are very close so well. they spend all their time outside in the bright sun, mostly looking at things off in the distance. (which, remember, so far as your eyes are concerned, are basically the same thing.)
Laurence Fraser. This makes sense in my case. As a child I spent most of my non school time outside or studying. Ok, mostly outside. It wasn’t until I started college and started working as a theatre technician (in the dark, working mostly up close or within 80 feet) that I started to loose my distance vision. Theatre work is mostly nights, so over those 25+ years I rarely saw the sun and when I did see it I often had to have sunglasses or close my eyes. In college I was diagnosed with astigmatism and most recently a touch of nearsightedness. I’ll be diversifying my vision practices and doing some of the old eye exercises I used to do.
It is screens and nonuniform light. Or candlelight reading like Malcolm X and Benjamin Franklin. The light supplied by screens is not uniform over time and the light is not uniform from pixel to pixel lines of words on a work computer or lines of actors on a tv show are not uniform. The eyes try to bend and relax to focus on what the brain thinks is the correct focal distance. This happens thousands of times a second. Sometimes, the eyes bend the lenses to focus slightly in front of the screen and then they will relax to focus slightly behind the screen. This constant bending and relaxing to match the fluctuations in the light from the screen will bend the lens to the point of the eye not being able to relax and see far away objects. Most people don't notice this happening because they have to bend their myopic/nearsighted lenses less to see near objects and these objects are still in focus. They don't realize that the far vision requires relaxation and they did about 1000 bicep curls per second with the lens trying to focus on the screen. Nook and Kindle in black and white use crystals to reflect light and do not cause myopia aka nearsightedness.
same.. i kinda feel like that's actually the reason why my eyes went bad as as a kid i used to do it alot in class whenever i was bored and this was about the same time as i started seeing blurry
A one... two-- A one... two... three... four... Half a bee, philosophically, Must, ipso facto, half not be. But half the bee has got to be Vis a vis, its entity. D'you see? But can a bee be said to be Or not to be an entire bee When half the bee is not a bee Due to some ancient injury? Singing... La dee dee, one two three, Eric the half a bee. A B C D E F G, Eric the half a bee. Is this wretched demi-bee, Half-asleep upon my knee, Some freak from a menagerie? No! It's Eric the half a bee! Fiddle de dum, Fiddle de dee, Eric the half a bee. Ho ho ho, tee hee hee, Eric the half a bee. I love this hive, employee-ee, Bisected accidentally, One summer afternoon by me, I love him carnally. He loves him carnally, Semi-carnally. The end. Cyril Connelly? No; semi-carnally! Oh. Cyril Connelly. [whistling]
Nearsightedness is caused by excessive time spent indoors as a child. This is why throughout history, eyeglasses were the mark of an educated man. Now that children play videogames rather than play outside, our eyes are getting worse and worse and worse. This is also why kids from certain Asian cultures have such high rates of nearsightedness.
My eyesight is pretty bat when it come to fine detail (astigmatism) . When I'm off in the woods I often don't ware my glasses and I don't have a problem catching small game, not falling into pits, or tripping over debris. I have noticed that print has been getting smaller over the years so I think it's is mostly a manufactured problem.
I love how you just glossed over the insanely blaring question with just "humans always had comfortable lives". I still liked the video even though it never answered the question
well the problem with UA-cam is that a majority of the time, your only space to get attention is the title or thumbnail. titles like this aren't really appropriate, but sometimes necessary to get new viewers.
That is not clickbait. He answer that question. He said that because of natural sepection animals with eye problems can't pass their genes because they die very easly. However humans can pass these genes.
Clickbait is something that does not offer what it says it would. Well, animals don't wear glasses "because they become food(prey) before they pass on their bad sight genes" as he clearly said. Think before talking, people !!
I used to have 20/10 vision (can read things at 10 feet that a 'normal' person can read at 20). As I've aged, my vision has gone to 20/20. Even though this is considered perfect vision, I still feel the loss, and as such have glasses to correct back to the 20/10 I used to have.
You must have been lucky that all your poor sighted relatives were killed off by natural selection so somehow the magic evolution fairy could give you good eyesight.
Inactivate the alarm! Only 29% of Americans (18 and older) don't require any type of corrective lenses, according to this Gallup poll: www.gallup.com/poll/3115/forty-percent-americans-who-use-glasses-would-consider-laser-eye-surgery.aspx (and keep in mind this is the most comprehensive data I could find, but it's from the year 2000, and likely a bit higher today)
+Steven Mathews I almost think corrective lenses harm the eyes natural vision. If it is genetic, that means we have severely screwed up. Since humans depend so much on eyesight, you would think we would have evolved better eyes. And bad eyesight isn't a modern phenomenon either, so there must be something else going on. I used to spend all my time indoors playing video games and have had challenges with friends as a kid where we stared at the sun to see who would last longer. And my eyesight hasn't deviated from the 20/20 range at all.
This lesson, though interesting at times, has a lot of misinformation. 1) muscles don't "squeeze" the lens. As an annular muscle contracts, the lens relaxes, making the lens "fatter" or more "round". It is a little complicated but this is "accommodation". 2) Myopia can be due to overall length or the curvature of the cornea/lens. 3) Astigmatism is not a "too round" cornea. It is a variation in the curvature of the cornea or lens resulting in parallel light being focused at 2 different points rather than a single point. It's one of the many types of optical aberration. Or it's a monster that kidnaps children. 4) Hyperopia is the opposite of Myopia. The lens doesn't "squish". If the lens relaxes and gets wider, in milder cases, the lens can actually function to correct hyperopia at near and distance. The key is: when the lens gets fatter, the focus comes forward. 5) Everyone gets presbyopia if they live long enough. Accommodation gets complicated as you age. 6) The diagram of the photo receptors (rods and cones) is wrong. They are oriented backwards the way shown in the video. Fun fact: the largest refractive surface of the eye is actually the tear film. When it comes to bending light, the cornea is more important than the lens (as far as power goes).
That's a great question that I never really thought about before. I started wearing glasses in fourth grade and I remember the first time I put on glasses the first thing I said was "I can see!" and was promptly returned to school.
It's definitely genetics in my family. I started to notice I was losing my sight in 5th grade and back then I spent a lot of time outside (often all afternoon). I read and wrote stories the other half of the time when it was dark out or rainy. I wasn't on computer much until high school, and I stopped losing vision before then. My eyes have been pretty stable ever since and I'm in my mid-twenties. I got my near sightedness from my dad, most of my aunts, uncles, cousins, etc. have some kind of vision problem. As soon as being able to see well wasn't necessary anymore due to living safer in communities more and more people with eye sight problems got to have kids and boom - we all can't see anymore because we don't need to (BTW, even before glasses we didn't need sight if others were protecting us- that's why we see animals acting as "seeing eyes" for other animals. I have heard several cases of this - a dog or horse leading a fellow member of their species around so they don't get into trouble). We can't really get a good study on how many people have a hard time seeing in other, poor countries where regular eyesight tests are uncommon. So comparing industrial countries to those less fortunate might not be the best comparison. Even if not getting enough sunlight is a problem, I think it just maybe makes you lose eyesight faster or just makes you lose it more - it's not the cause. I think the basis for it is genetic. Sun will help, maybe slow it down, but probably not prevent it.
My eyesight is 15/20. I wasnt raised in front of the TV or on portable devices. You want your eyesight to improve then spend some good time in nature. My wife had horrible eyesight when I met her but from going out in the woods often her eyesight has improved to the point she doesnt need her glasses...before she was heavily dependant on them.
What about ppl who got 1 eye faulty (like me, 1 does blurry image at distance) and 1 healthy ? I don't wear glasses. Using both at same time gives very sharp detailed vision. No health issues , and its very sharp very precise.
Both my mom and dad wear glasses and i, do far, havent needed to. But i am becoming far sighted. Used to be able to focus on something 4 inches from my eyes but now have difficulty
I have myopia and astigmatism. I started wearing glasses when I wasn't 13 yet (in 1998). I could never have a laser surgery due to a problem called fetal cataract. At least that's what the eye doctor told me.
after a few videos on your channel your way better than v sauce !!! you dont shove unsure science down our throats and remain curious and heuristic.. good job !! its ok to be smart ;)
I wore glasses for the beginning of my childhood from 1st to 3rd grade. My eye sight actually was corrected and I haven't worn glasses through the rest of my childhood to the present day of adulthood. I didn't get surgery or get contacts.
What I wonder: even if "wrong-sighted" the picture sometimes can get sharp if you focus on the wrong distance (you want to see an object in 3m distance, it's blurry, you focus right behind in 4m and the thing in 3m gets sharper), why? O.o why doesn't the brain just focuses until it's sharp, but instead uses (sometimes) the programmed distance?
I was literally asking my mom about our eyes and evolution this morning and then I just saw this pop up on UA-cam! Weird coincidence, but thanks for helping to answer my questions lol
3:51 Part of the reason there is an increase in corrective lenses(blindness), is because they read things in poor light conditions, causing an increase in the eye length.
You made it seem like myopia and astigmatism are both corrected the same way (i.e. with a simple minus lens) rather than astigmatism requiring a toric lens. What gives?
my whole family wears glasses but i don't... the bright lights thing makes sense I guess, I used to have competitions with my sister for who could stare at the sun the longest and I always won.
Here is a question that's been bugging me. When you close your eyes sometimes you can see flashes of color and waves some times kaleidoscope. Blind people can "see" this too even if theyve always been blind. And it is known that humans can't see all the colors. We can also produce images in our brain that we haven't seen irl. Which brings me to my question: Can we imagine colors that we can't see or produce images of colors invisible to the eye in our brain? And how if possible?
I rarely wear my glasses. When things are far away I can't really see details, but I'm fine with not seeing as good as others. You don't need to see perfectly, you just need to see enough. In the wild, when a dangerous animal is nearby, you don't have to necessarily see what it is, it's enough to see if it's big, what color it is and if it walks on four or two legs. That's all you really need to know, you might run away when it's really not dangerous, but better safe than sorry
Because the lens is deformable and controlled by muscles of accommodation, after an animal is born there is some latitude for compensation to optimal focal distance. Certainly over months of use muscles can hypertrophy or relax to adjust for the distance where use is most common. Dogs use their vision mostly for far objects and so naturally become farsighted, using smell for any small object closer than a few feet. However humans use vision for many tasks at widely varying focal distances, and of course we're in a position to complain when things aren't exactly right. So I'm not so sure that our eyes are that much inferior to those of animals in the wild.
I was actually ruminating on this topic recently (and was surprised to see this in my suggestions). IIRC, in general presbyopia is lessened in people with myopia, so I wondered if it's possible that myopia has existed in human populations ever since the development of more complex tools as a way to extend the useful life of humans beyond the age that presbyopia would prevent fine tool working. In other words, mild myopia would have very little detriment to those who's primary tasks weren't hunting or warring but rather crafting, and could delay the onset of near-nearsightedness and therefore infirmity.
One of the only people in my family who escaped the need for glasses. In fact, I have 20-12 vision, which is better than the minimum ideal of 20-20. I only get to enjoy the perk for so much longer, however. Based on family history, I'll get about another 10 years before I need reading glasses.
since we spend so much time staring at near objects like computer and phone screens, why dont we wear special glasses that make the image appear further than it really is? That should help reduce eye strains
Myself and my dad's side of the family all have above average vision...and we also always get compliments on having nice/pretty eyes. I wonder if eyes that work really well somehow look better to mates haha.
How well does Laser Eye surgery work? It’s just that I’m quite young and although my prescription is very small (tiny, really) it gets worse every time I visit the optician’s. I don’t want to have terrible eyesight by the time I’m, say, 50.
All other animals that wore glasses were weeded out by natural selection due to being punched in the face for looking too nerdy.
lol
XD underrated
Lmao
@@pinkajou656 ぴン까죠う
Have you tried putting classes on a deer? Don't even get me started on a tigers. It took me forever to clean the blood. I'll never forget you Jimmy.
Just try putting glasses on sharks. I died trying.
+O sorry for your loss
Gothicscull234Gmail "wanna know how i got my scars" much
uhhhhhhhhhhhhhhh
Rip Jimmy
Some of the information in this video is incorrect.
1. The majority of the refracting power of the eye is from the cornea, approximately 45 diopters worth while the lens is only approximately 15 diopters worth.
2. We don't "squeeze and pull" the lens. The lens has a certain shape that it "wants" to be in, or it's relaxed position, that which allows us to see farther objects and it is the more rounded shape. When we focus with the lens to see objects up close to us, the ciliary muscle pulls the lens to flatten it.
3. Astigmatism is not caused by the cornea being too round. Instead it's because the cornea has different refracting powers in different meridians. For example, the cornea may have a different refracting power at the up/down meridian versus the left/right meridian. A lot of people are worried by the diagnosis of astigmatism. But in reality the majority of people have at least some astigmatism, something like >80% of people.
My source? I am an eye doctor...
You should have dropped the mic dude.
BRUH...
Oh
Lol, I was about to type this.
@@slanguagefreak2388 you make me laugh sad clown
This video actually taught me a lot of stuff that I didn't even know I would be interested in!
Well... Maybe because they can't make glasses?
Humans are animals, so technically animals can make glasses.
+Andreas Tollånes (FanzyPantz) They need opposable things and the knowledge on how to forge glass into shaped with different focal lengths. Which I doubt animals like rabbits or frogs can xD
Opposable thumbs*
That, and they probably just get used to their eyesight that correction would be too strange and possibly deadly for them if they couldn't learn to adapt to it.
Probably because they are better than us. Just better than us.
Take a look at how our eyes make clear images… or don't. Pretty interesting stuff (or at least eye think so)
Nice puns
When I saw this video I was thinking about when I tried putting my glasses on one of my pet bunnies, and they knock it off. And yes, I need my glasses to see words from far away(I can see fine without glasses, but they help me see more specific details). Guess my bunnies hate glasses XD
I need my glasses; wait here.
I SEE what you did there.
+Master Therion eye*
Because any animal that needs glasses dies as soon as he doesn'see a prey or predator .. Done
+James Pham yeah, but they won't see a tree in their way, or hole in the ground
+Setillos how much does it take to see a hole big enough for you to fall in or a tree big enough for you to run in. you can be practically blind and still be able to.
+Dotz yeah, unless you are distracted by upcoming death and/or have narrowed vision like such animals and you can see mostly only central part of what's in front if you.
Also, that hole/tree doesn't need to be big.
Hole needs to be big enough to make you lose your balance so it doesn't need to be that big and tree just has to be big enough for you to trip over it.
Most canine species have pretty bad eye sights compared to us humans in general. They have their other senses as compensation. We humans are heavily focused on our eyes as main medium of information around us.
and he can't get them
I'm SO glad you brought up the "time outside" reason! When I first read about that, I was super excited, because it's yet another reason for what I do.
Eyes are the one thing I am ridiculously squeamish about. I can't handle looking or even thinking about things touching my eyes. I have to turn away every time my sisters put their contacts in.
All that to say, that sudden close up of someone putting their contacts in made me almost fall out of my chair.
Edit: Oh yeah, the video was great too. :P
Oh wow haha. That's rough
Then you should definitely not watch Un Chien Andalou.
I am the same way! Eyes freak me out so much
I am the same way. I don't really like having glasses, but I use them because the thought of touching my eyes to put contacts in kills me. My greatest fear is getting a needle in the eye....
same except something about the eyes bother me i cant resist but put my hands near my eyes once i saw a video where a cat scratches a girls eye after that i felt like fainting
I have had my natural lense removed beacuse of injury, and have been confused for ages on why I have hade been able to see in rooms lit with a blacklight, as they were lit by a normal violet light. The final part of the video explained a long time cofusion in my life! Thanks dude!! :D
doctor: read the first line you can see
cow: *moo*
This was supposed to be about animal eyes, not human eyes
Humans are animals, but I get your point. The title does say "other animals" implying other than human animals.
The title is obviously tongue-in-cheek.
it wasn't supposed to be about animal eyes, it just happens that animal eyes are involved in the question presented in the title
Astigmatism is caused by the cornea not being symmetrically curved in all directions, not that it is too round.
PatCh lack of symmetry can be vertical, horizontal, or idiopathic. Most common is vertical (causing the bulge)
Great video! You hit so many great points! Just a quick clarification (with recap). Refractive error (myopia or hyperopia) is caused by the axial length of your eye (correct in the video) and the power of your cornea.....only a minor part from your lens. The lens will naturally try to accommodate (flex) to bring objects in focus but some individual's refractive error (hyperopia) is too great for it to overcome. As we get older, we lose the ability to accommodate (presbyopia) and have a higher need for glasses (most of us at near but some for near and far). Since 78% of the refractive power of the eye comes from the cornea, the lens plays a smaller role by fine tuning it. If you have a myopia (near sightedness) it is because your cornea is too powerful or the axial length of the eye too long. The opposite is true for hyperopia (far sightedness). When we perform cataract surgery (replacing the natural lens with an artificial one), the power of the lens doesn't carry much weight in determining the power of the artificial lens. The corneal power and axial length are very important though! In case you're wondering my background, I'm an ophthalmologist and have spent way way too long studying this :) Feel free to see my eye tips at facebook.com/TheEyeMD2016/
wait, so why don't animal wear glasses ?
Because animals with bad sight, in an environnement where sight is essential, don't survive well. Yup, natural selection ! We, humans and our health care, are (trying to) outsmarting natural selection.
Kind of like the Azgards in StarGate.
They will with enough duct tape.
Because they find it uncomfortable
Because humans are the only animal that's able to work with glass and comprehend how lenses work and how to make them.
That's one part of the real answer.
Because they can rely on other senses to get by
Fun fact - humans can only focus onto the retina in one way. Birds of prey can do it two ways. Meaning they can focus at incredibly high distances for hunting, but also close up, like in their nests.
What are those ways?
Every one in my family has glasses except me!!!!!!
😂😂😂😂😂😂😂😂😂
Joe really reminds me of Chidi from the Good Place in this video. It's mainly the style of shirt and glasses, but also kinda his mannerisms and even face shape
I have kerataconus - where the cornea takes on a more conical shape than a hemispherical one. One of the "treatments" for it is soaking the eye with Vitamin B12 and exposing it to UV light (UV-B I believe), which increases the cross-linking of the collagen in the cornea - though I put "treatment" in quotes because that doesn't actually reverse the condition, it only helps prevent it from getting worse.
I've never seen an experiment that specifically checks, but I've suspected for a while that the 'excessive' use of sunglasses during adolescence (when most people start to exhibit the issue) may contribute to the developing of this condition, as it would deprive the eyes of levels of UV that may be required to keep the eye's shape from distorting over time, particularly while the body is going through the changes of puberty.
But I'm not a scientist, so, who knows.
Hey I have developed the same condition so after 4 years is there any improvement
@@TECH-hg7yp No, its _mostly_ stabilised - but I'm told that, short of some sort of surgery, it'll only ever get worse.
I remember hearing a theory that people with bad eyesight are the reason for most myths/mythological creatures or legends.
I know this is an older video, but I wonder, if adults between 30-40 years old wear sunglasses more often than necessary does that mean that they will have trouble focusing when they're older?
i love this channel i always learn something new whenever something new gets posted
when every fish sees better then you
My dog use to wear glasses. As kids we would put our glasses on him and he'd walk around the house. He seemed to like it. He also use to find chewed gum in the garbage and start chewing it. He loved gum and glasses. I miss my dog.
So.... Staring at a screen watching UA-cam everyday isn't a risk of needing to wear glasses?
It is
+jwin_the_pro But if you are a sloth, you don't have to.
As long as u go out and stare at the sun
This >> endmyopia.org/end-myopia-home/
Gothicscull234Gmail lol
One of my horses needs glasses. He definitely can't see as well as my other horse. My other horse notices things at distance and close up. I think that is why he likes to follow other horses and not lead, plus needs an assist sometimes to find things. Come with me and let me show you where I put the hay out in the yard.
my vision started to go my freshmen year in high school and from when i was a kid till then i was outside every moment i could outside of school. so just going to school takes you out of the sun enough to have that large an effect? but why aren't my eyes getting worse? they've been the same and now i never leave the damn house.
human eyes become rounder over time becoming worse. i got glasses when i was 13 when i couldn't see the chalkboard in school. I'm 19 now don't go outside except when i have to and my eyes are stagnant since when they got bad. Really weird.
Well your mileage may vary.
i dont know, i'll just blame vaccines :P
Your eyes stop growing at any appreciable rate past your early 20s, and generally have slowed significantly by the late teens. It's possible for your eyes to change after those years (aside from presbyopia which is common past age 50), but generally quite slowly. So sunlight or no your eyes won't change much if you're past your main growth years.
KingdomOfDimensions, this comment exactly why having shitty eyesight isn’t entirely caused by environmental factors.
Just discovered this channel. And it's awesome! You have excellent content. Thanks a lot!
Can you find a scientific reason why I'm always attracted to girls with glasses?
because you want blind deformed children who will grow up to resent you for being stupid
I've been using The Great Courses for more than a year now, and I definitely recommend it, especially for us, addicted to knowledge.
my first thought when i saw the title: cause they cant make them, duh
Please do an episode on ghosts! What we know, what disproves them, and what keeps the stories alive.
I wonder what my eyeshape is, I have both myopia and astigmatism (thanks dad)
Likely elongated with a warped cornea.
Highfive!!
I have astigmatism
I have myopia in one eye and the other is fine
Many people who need glasses around me (me included) have both. I started developing astigmatism after being diagnosed with myopia. I guess it's a common thing
I also heard that the act of starting to wear glasses if the prescription is a bit too strong can make your eye sight worse too
Should post videos more frequently
Ha. This guy. Weekly isn't good enough for ya? :)
Not at all. We need more of your videos! Daily! My boredom and interest in random science facts must be fed man!
EDIT: (For the few of you who didn't know, I was joking. Soo... yeah. xD)
Yeah, becayse they are nade in just one day having this ammount of quality on content and animations...
+Fastest Crafter Then make your own videos
+It's Okay To Be Smart I guess not.
But being a little nearsighted is helpful to literally focus on reading and precision work like soldering. Try taking a photo up close and you will see the image gets blurry
Then there are people who naturally have better vision in general so they are able to do very detailed work and see very far, these people likely just have a better focusing mechanism/better visual system.
Yeah but people who have perfect 20/20 vision could literally do the same thing the human eye is support adjust to see certain things in front of us or a little bit away
through meditation I've found my lense muscles and now can flex them on command.
20/20 vision baby!! :-D
TEACH ME YOUR WAYS !
Really? Can you post a link mentioning this technique? It'd be very interesting to look into it.
Niker107 it was something I discovered myself at a young age while starring into the magic eye books
+Pikapetey Animations that makes two of us ;)
OMG PIKAPETEY!
I cant believe I'm saying this, I've thought about it, and I thought I never would.
The best part about this video, was the sponsor. That site rocks man thanks!
Ah so what you're saying we need bionic eyes?
When i dont have my glasses i take a picture of what i need to see and look at it
Anonymous thats hilarious but effective!
I have very mild nearsightedness but my astigmatism is worse.
It gets worse for me after every blow to the head I get (active teen and very unlucky when it comes to cars I’m passengering in). And I’ve not gotten an eye exam since my last concussion. But my glasses still work 90% of the time.
My optometrist said it probably gets worse after a blow to the head due to internal pressure changes bulging the lense and it doesn’t fully return to normal. And is why blurry vision is a post concussion symptom
which software do you use to make these videos ??? #itsokaytobesmart
Aryan Mehra . Hey we have same surname. I too wanna know.
Interesting, right now I'm working on a science video which explains a lot of the mechanisms not quite touched upon here, such as why the lens stops working and what factors including sunlight affect eye growth, and how they make us more near sighted. However, most animals are in fact more nearsighted/have blurrier vision than us so a tight regulated eyeshape is a bit less important. Dogs have 20/75 vision for instance. Only birds have overall better acuity, but that is because they are selected for high resolution vision. Most animals in fact don't rely on vision as their primary sense, and that is why it doesn't matter if their eyesight isn't perfect, which it often isn't anyway ;)
Geeks can't bend light properly..
Neither can you.
People that use screens can't bend light correctly because they were not told that screens which supply light to the eye are not uniformly lit. This causes the eye to bend and relax thousands of times a second trying to focus slightly in front of the screen and then slightly behind the screen. This bends the lenses just like doing thousands of bicep curls could hurt the arms. the lens get more long (protruding from face basically) and it cannot relax to see far away anymore.
Eye strain is pre-myopia. Ben Franklin and Malcom X both read by candlelight and needed glasses. Smart people are smart enough to not need glasses but nobody is ever told the truth because we need stupid workers who blame everything on genetics and these workers cannot question anything.
@@gregbernard4466 r/whoosh
@@gregbernard4466 Bruh...
@@gregbernard4466 bruh what lmao I probably have way better vision then u and I also don't need glasses also what are u using to type your comment
There's a lot of nearly correct but not quite information in this video.
There are two main causes that determine a need for spherical correction which is either the length of the eye as mentioned or the surface radius of curvature.
Astigmatism is a non-spherical cornia (so rugby ball shaped 🏉) causing different meridians to have different radius of curvature.
If a crystalline lens has to accommodate to focus on an object at 6m or further then you would still need a prescription because the prescription is measured against the unaccommodated eye.
I still don't buy the sunlight thing i think it would be far more likely that the reason is you spend so much time inside sun or not. this would mean that your eyes never have to see far only at most a few feat to the next wall.
I agree with you there
it's not sunlight specifically, so much as amount of light total. lots of bright florescent light will tend to cause less issue than inadequate incandescents of lower brightness, for example (though if you're in any way light sensitive, have their own issues. these days you can get LED bulbs though, which are Great for having few or none of the down sides of either.)
Bonus points: your eyes make the Exact Same Adjustment to deal with stuff that's really close that they do to deal with low light environments, and the same is true of really bright environments and things which are really far away. So if one causes problems, so does the other.
you can get away with looking at stuff up close a lot if you're also in bright light a lot (doesn't have to be at the same time) for example, because the problems comes from your body adopting a natural "rest" position at whatever point you use most, and then it's ability to change that decaying due to what is almost literally a lack of exercise.
if you're in dim environments a lot, your eyes will adjust so it's easier to see things from closer in, which will tend to lead to you holding books closer to your face and such, among other things.
I actually have the problem. My eyesight is deteriorating quite noticeably because, due to other health issues causing rather crippling head pains with associated light sensitivity (and a problem where my lenses don't focus different Colours properly, and a mental problem which means my brain doesn't filter things enough so more light/sound/etc = bad) i spend a Lot of time in low light environments. My brother, who spends as much if not more time than me in front of computers and the like, but typically has brighter lights where he does so, and spends a lot more time outside (if only travelling too and from the University), has Much better eye sight.
meanwhile, from memory, the various groups who live(ed) on the Mongolian steppe, or in other bright, open environments, typically have better vision over all... and when they Do have problems it's most commonly that they can't see things which are very close so well. they spend all their time outside in the bright sun, mostly looking at things off in the distance. (which, remember, so far as your eyes are concerned, are basically the same thing.)
Laurence Fraser. This makes sense in my case. As a child I spent most of my non school time outside or studying. Ok, mostly outside. It wasn’t until I started college and started working as a theatre technician (in the dark, working mostly up close or within 80 feet) that I started to loose my distance vision. Theatre work is mostly nights, so over those 25+ years I rarely saw the sun and when I did see it I often had to have sunglasses or close my eyes. In college I was diagnosed with astigmatism and most recently a touch of nearsightedness. I’ll be diversifying my vision practices and doing some of the old eye exercises I used to do.
It is screens and nonuniform light. Or candlelight reading like Malcolm X and Benjamin Franklin. The light supplied by screens is not uniform over time and the light is not uniform from pixel to pixel lines of words on a work computer or lines of actors on a tv show are not uniform. The eyes try to bend and relax to focus on what the brain thinks is the correct focal distance. This happens thousands of times a second. Sometimes, the eyes bend the lenses to focus slightly in front of the screen and then they will relax to focus slightly behind the screen. This constant bending and relaxing to match the fluctuations in the light from the screen will bend the lens to the point of the eye not being able to relax and see far away objects.
Most people don't notice this happening because they have to bend their myopic/nearsighted lenses less to see near objects and these objects are still in focus. They don't realize that the far vision requires relaxation and they did about 1000 bicep curls per second with the lens trying to focus on the screen. Nook and Kindle in black and white use crystals to reflect light and do not cause myopia aka nearsightedness.
I can voluntarily loose focus with my eyes.
same.. i kinda feel like that's actually the reason why my eyes went bad as as a kid i used to do it alot in class whenever i was bored and this was about the same time as i started seeing blurry
@@litchtheshinigami8936 lmao 😂
i wanted to laugh so hard because the eye picture looks like a bird.
A one... two-- A one... two... three... four...
Half a bee, philosophically,
Must, ipso facto, half not be.
But half the bee has got to be
Vis a vis, its entity. D'you see?
But can a bee be said to be
Or not to be an entire bee
When half the bee is not a bee
Due to some ancient injury?
Singing...
La dee dee, one two three,
Eric the half a bee.
A B C D E F G,
Eric the half a bee.
Is this wretched demi-bee,
Half-asleep upon my knee,
Some freak from a menagerie?
No! It's Eric the half a bee!
Fiddle de dum, Fiddle de dee,
Eric the half a bee.
Ho ho ho, tee hee hee,
Eric the half a bee.
I love this hive, employee-ee,
Bisected accidentally,
One summer afternoon by me,
I love him carnally.
He loves him carnally,
Semi-carnally.
The end.
Cyril Connelly?
No; semi-carnally!
Oh.
Cyril Connelly.
[whistling]
I literally can't understand this.
I have overloaded on vocabulary.
its a monty python song
Take it away, Eric the orchestra leader...
Nearsightedness is caused by excessive time spent indoors as a child. This is why throughout history, eyeglasses were the mark of an educated man. Now that children play videogames rather than play outside, our eyes are getting worse and worse and worse.
This is also why kids from certain Asian cultures have such high rates of nearsightedness.
thumbs if you wear glasses, nasty comment if you do not. I do wear glasses so, first like!
doesn't look like it
You are very noob
Blah blah lol
You can't even try to get likes. You just ask a certin group of people to give you likes. There you go.
Nasty comment
My eyesight is pretty bat when it come to fine detail (astigmatism) . When I'm off in the woods I often don't ware my glasses and I don't have a problem catching small game, not falling into pits, or tripping over debris. I have noticed that print has been getting smaller over the years so I think it's is mostly a manufactured problem.
Yet another thing Pokemon Go did right.
I love how you just glossed over the insanely blaring question with just "humans always had comfortable lives". I still liked the video even though it never answered the question
clickbait titles shouldn't be that regular on this channe
I was about to say the same. I almost skipped this video because the title seemed unusually unintelligent for this channel.
well the problem with UA-cam is that a majority of the time, your only space to get attention is the title or thumbnail. titles like this aren't really appropriate, but sometimes necessary to get new viewers.
That's not clickbait. Stop calling everything clickbait.
That is not clickbait. He answer that question. He said that because of natural sepection animals with eye problems can't pass their genes because they die very easly. However humans can pass these genes.
Clickbait is something that does not offer what it says it would. Well, animals don't wear glasses "because they become food(prey) before they pass on their bad sight genes" as he clearly said. Think before talking, people !!
I am so very very thankful for multi-focal contact lenses that allow me to see both far away and up close...
"kinda football shaped" u mean american egg shaped
handegg shaped
Excelente vídeo, gracias por el magnifico trabajo.
First,,, here's two jokes
Hillary and Trump
3rd joke. The brexit
Shut up, Sophie.
Aliens made Bernie sanders loose
+CeaoS I'm as disappointed as you are, if not more. That's why it's the biggest joke going 😒
Sophie K
neither side has really won ... and saying the other side is a joke is immature and naive
I used to have 20/10 vision (can read things at 10 feet that a 'normal' person can read at 20). As I've aged, my vision has gone to 20/20. Even though this is considered perfect vision, I still feel the loss, and as such have glasses to correct back to the 20/10 I used to have.
You must have been lucky that all your poor sighted relatives were killed off by natural selection so somehow the magic evolution fairy could give you good eyesight.
Lol, well I didn't pass it down to my son. He's tragically near sighted. I blame my wife's genes.
where does the "7 out of 10 Americans" statistic come from?
my bullshit alarm is ringing loud and clear
Inactivate the alarm! Only 29% of Americans (18 and older) don't require any type of corrective lenses, according to this Gallup poll: www.gallup.com/poll/3115/forty-percent-americans-who-use-glasses-would-consider-laser-eye-surgery.aspx
(and keep in mind this is the most comprehensive data I could find, but it's from the year 2000, and likely a bit higher today)
fair enough, but you do science videos; shouldn't you cite all sources under the video?
+It's Okay To Be Smart Wow, I'm in the minority, incredible.
that is amazingly surprising..
gonna have to recalibrate my bullshit alarm
70% of people are genetically defective... hmm
+Steven Mathews I almost think corrective lenses harm the eyes natural vision. If it is genetic, that means we have severely screwed up. Since humans depend so much on eyesight, you would think we would have evolved better eyes. And bad eyesight isn't a modern phenomenon either, so there must be something else going on. I used to spend all my time indoors playing video games and have had challenges with friends as a kid where we stared at the sun to see who would last longer. And my eyesight hasn't deviated from the 20/20 range at all.
This lesson, though interesting at times, has a lot of misinformation. 1) muscles don't "squeeze" the lens. As an annular muscle contracts, the lens relaxes, making the lens "fatter" or more "round". It is a little complicated but this is "accommodation". 2) Myopia can be due to overall length or the curvature of the cornea/lens. 3) Astigmatism is not a "too round" cornea. It is a variation in the curvature of the cornea or lens resulting in parallel light being focused at 2 different points rather than a single point. It's one of the many types of optical aberration. Or it's a monster that kidnaps children. 4) Hyperopia is the opposite of Myopia. The lens doesn't "squish". If the lens relaxes and gets wider, in milder cases, the lens can actually function to correct hyperopia at near and distance. The key is: when the lens gets fatter, the focus comes forward. 5) Everyone gets presbyopia if they live long enough. Accommodation gets complicated as you age. 6) The diagram of the photo receptors (rods and cones) is wrong. They are oriented backwards the way shown in the video. Fun fact: the largest refractive surface of the eye is actually the tear film. When it comes to bending light, the cornea is more important than the lens (as far as power goes).
who here has glasses
me
me
me
Im suppose to, but i see fine.
+Lovezys123 Lucky! I can't read from my computer screen if its more than 1m away without my glasses :/
That's a great question that I never really thought about before. I started wearing glasses in fourth grade and I remember the first time I put on glasses the first thing I said was "I can see!" and was promptly returned to school.
It's definitely genetics in my family. I started to notice I was losing my sight in 5th grade and back then I spent a lot of time outside (often all afternoon). I read and wrote stories the other half of the time when it was dark out or rainy. I wasn't on computer much until high school, and I stopped losing vision before then. My eyes have been pretty stable ever since and I'm in my mid-twenties. I got my near sightedness from my dad, most of my aunts, uncles, cousins, etc. have some kind of vision problem.
As soon as being able to see well wasn't necessary anymore due to living safer in communities more and more people with eye sight problems got to have kids and boom - we all can't see anymore because we don't need to (BTW, even before glasses we didn't need sight if others were protecting us- that's why we see animals acting as "seeing eyes" for other animals. I have heard several cases of this - a dog or horse leading a fellow member of their species around so they don't get into trouble). We can't really get a good study on how many people have a hard time seeing in other, poor countries where regular eyesight tests are uncommon. So comparing industrial countries to those less fortunate might not be the best comparison. Even if not getting enough sunlight is a problem, I think it just maybe makes you lose eyesight faster or just makes you lose it more - it's not the cause. I think the basis for it is genetic. Sun will help, maybe slow it down, but probably not prevent it.
4:10 i flinched when he said 2020
My eyesight is 15/20. I wasnt raised in front of the TV or on portable devices. You want your eyesight to improve then spend some good time in nature. My wife had horrible eyesight when I met her but from going out in the woods often her eyesight has improved to the point she doesnt need her glasses...before she was heavily dependant on them.
What about ppl who got 1 eye faulty (like me, 1 does blurry image at distance) and 1 healthy ? I don't wear glasses. Using both at same time gives very sharp detailed vision. No health issues , and its very sharp very precise.
So if good eye sight is coming less common in the youth, does that mean the fact that i'm 21 and have perfect vision is uncommon/rare?
Both my mom and dad wear glasses and i, do far, havent needed to. But i am becoming far sighted. Used to be able to focus on something 4 inches from my eyes but now have difficulty
I have myopia and astigmatism. I started wearing glasses when I wasn't 13 yet (in 1998). I could never have a laser surgery due to a problem called fetal cataract. At least that's what the eye doctor told me.
after a few videos on your channel
your way better than v sauce !!! you dont shove unsure science down our throats and remain curious and heuristic..
good job !!
its ok to be smart ;)
I wore glasses for the beginning of my childhood from 1st to 3rd grade. My eye sight actually was corrected and I haven't worn glasses through the rest of my childhood to the present day of adulthood. I didn't get surgery or get contacts.
What I wonder: even if "wrong-sighted" the picture sometimes can get sharp if you focus on the wrong distance (you want to see an object in 3m distance, it's blurry, you focus right behind in 4m and the thing in 3m gets sharper), why? O.o why doesn't the brain just focuses until it's sharp, but instead uses (sometimes) the programmed distance?
I was literally asking my mom about our eyes and evolution this morning and then I just saw this pop up on UA-cam! Weird coincidence, but thanks for helping to answer my questions lol
3:51 Part of the reason there is an increase in corrective lenses(blindness), is because they read things in poor light conditions, causing an increase in the eye length.
I've asked so many of my eye doctors these questions. Thanks for answering them
You made it seem like myopia and astigmatism are both corrected the same way (i.e. with a simple minus lens) rather than astigmatism requiring a toric lens. What gives?
I sometimes feel weird because I don't need corrective lenses.
Ohh shittt!!! This question used to come to my mind so many times!! And feels crazy to see a video about it!👍
my whole family wears glasses but i don't... the bright lights thing makes sense I guess, I used to have competitions with my sister for who could stare at the sun the longest and I always won.
Here is a question that's been bugging me. When you close your eyes sometimes you can see flashes of color and waves some times kaleidoscope. Blind people can "see" this too even if theyve always been blind. And it is known that humans can't see all the colors. We can also produce images in our brain that we haven't seen irl. Which brings me to my question: Can we imagine colors that we can't see or produce images of colors invisible to the eye in our brain? And how if possible?
I really like this channel and all but that overwatch reference at the beginning
Winston just made me like them more 😂😂😂
Dat cat on the sofa arm at 1:05 is adorable.
I rarely wear my glasses. When things are far away I can't really see details, but I'm fine with not seeing as good as others. You don't need to see perfectly, you just need to see enough. In the wild, when a dangerous animal is nearby, you don't have to necessarily see what it is, it's enough to see if it's big, what color it is and if it walks on four or two legs. That's all you really need to know, you might run away when it's really not dangerous, but better safe than sorry
I have 20/10 vision like all my siblings, but both of my parents have had vision problems since they were young.
I like that I had an un-skippable contacts ad before this vid
Because the lens is deformable and controlled by muscles of accommodation, after an animal is born there is some latitude for compensation to optimal focal distance. Certainly over months of use muscles can hypertrophy or relax to adjust for the distance where use is most common. Dogs use their vision mostly for far objects and so naturally become farsighted, using smell for any small object closer than a few feet. However humans use vision for many tasks at widely varying focal distances, and of course we're in a position to complain when things aren't exactly right. So I'm not so sure that our eyes are that much inferior to those of animals in the wild.
I was actually ruminating on this topic recently (and was surprised to see this in my suggestions). IIRC, in general presbyopia is lessened in people with myopia, so I wondered if it's possible that myopia has existed in human populations ever since the development of more complex tools as a way to extend the useful life of humans beyond the age that presbyopia would prevent fine tool working. In other words, mild myopia would have very little detriment to those who's primary tasks weren't hunting or warring but rather crafting, and could delay the onset of near-nearsightedness and therefore infirmity.
One of the only people in my family who escaped the need for glasses. In fact, I have 20-12 vision, which is better than the minimum ideal of 20-20.
I only get to enjoy the perk for so much longer, however. Based on family history, I'll get about another 10 years before I need reading glasses.
As a kid I'm pretty sure I put a laser light right up to my eye for like 10 seconds. Also one of my eyes are much darker brown than the other
since we spend so much time staring at near objects like computer and phone screens, why dont we wear special glasses that make the image appear further than it really is? That should help reduce eye strains
could the recent change in diet be a factor? (veg/seed oil is around 100 years new)
Myself and my dad's side of the family all have above average vision...and we also always get compliments on having nice/pretty eyes.
I wonder if eyes that work really well somehow look better to mates haha.
is there any way we could make glasses that would allow us to see in the ultraviolet? cause, that would be cool.
General physics 3 in 6 minutes. You are amazing.
My tired brain at 3AM
This current video is very interesting like the other published videos that have been uploaded by this specific channel.👍🏽😏😲😲👀
Great video, great work!! Can you produce your videoes in 4K please? (I know this is easier said than done) - but it's not sharp enough! ;-)
When an animal wears glasses, a minus lens, the primate becomes myopic.
How well does Laser Eye surgery work? It’s just that I’m quite young and although my prescription is very small (tiny, really) it gets worse every time I visit the optician’s. I don’t want to have terrible eyesight by the time I’m, say, 50.
You guys should make a video on the physics of black holes and the theories behind them. I don't know I just find them really interesting... :)