Why do you see better when you squint? – Big Questions – (Ep. 33)


Hi I’m Craig, and this is Mental Floss on
YouTube. Today, I’m going to answer Amar Jerath’s big question, “Why do you see
better when you squint?” Let’s get started! In order to answer this question, I’m going
to have to talk a little about how the eye works JUST IN CASE you weren’t paying attention
in science class. So, the whole reason we can see is thanks
to our good friend light. While you’re looking at something, light is entering the pupil.
The lens in your eye lives right behind the pupil and that focuses the light on the retina. The retina is a layer of tissue containing
photosensitive cells, known as rods and cones. And that’s where the image (of what you
see) is created, then that image gets sent to the optic nerve in the brain. In the retina,
there’s something called “fovea,” which is the part of the eye that makes sharp central
vision (a.k.a. detail-oriented vision) possible. We need that type of vision so we can do stuff
like read and drive. When you look at an object and it appears
blurry, that’s usually because of light too. The lens doesn’t properly focus the
light onto the retina. (Unless you have another eye condition, like cataracts, causing this
to happen.) When you squint, two things change that help
you see better: the shape of your eye and the amount of light entering it. And a third
thing, you look like Gilbert Gottfried. If you know who that is. First, there’s the shape. When a person
squints, the new shape of the eye makes it so that the light coming into the eye can
be focused directly on the fovea. And since the fovea is the best at getting visual details,
that helps us see more clearly. Second, there’s the amount of light entering
the eye. When someone squints, less light is let into the eye. Blocking out a bunch
of unnecessary, excess light makes it easier for the eye to focus because it’s trying
to focus on less all at once. This can really help when you’re in a bind,
but it’s probably worth mentioning that if you’re frequently squinting in order
to see…you might need glasses. Or if you already have them, you need to stop forgetting
to wear them. You go get your glasses. But, contrary to popular belief, squinting isn’t
going to damage your vision. It might give you a headache, but that’s just because
of the muscle contraction in your face. It also might give you these things. What are
they called, angel tears? Crow’s feet. Thanks for watching Mental Floss on YouTube,
which is made with the help of all these foveas. If you have a Big Question of your own that
you’d like answered, leave it below in comments. See you next week!

100 comments

  1. Dear Mental Floss,
    Can you possibly do a video on either facts or misconceptions about Edgar Allen Poe?

    I just think it's incredibly unfair that the man that had been left in charge of Poe's legacy (his literary executor Rufus Wilmot Griswold) not only hated him intensely but was also a lying liar who lied. Schools are still repeating his slander, teaching kids that Poe was a drunkard and/or a drug addict for Tesla's sake!

    Please spread the truth about this brilliant, highly misunderstood man.

    Best wishes,
    Edith

  2. So the real answer to "Why do you see better when you squint?" is, you don't if your eyesight is good. If it helps you, it helps even more visiting a good optician.

  3. Do a, " why do your eyes sting if you open them in chlorinated water" that would be amazing😀😀

  4. The same effect is achieved by looking through a pinhole (no squinting!) and doctors use this to help their patients. This simple, yet important test tells you that if your vision improves through a pinhole, the problem is called a "refractive error" and is easily fixed with eyeglasses. However, if your vision is the same or worsens through a pinhole, then your blurry vision is most likely caused by something else. It's as simple as poking a piece of paper with a safety pin, tack or paperclip. Try it! 🙂

  5. I'm confused – in my experience, squinting just makes things blurry. Is this just me? Is people squinting to see better a common thing?

  6. Hank Green told me i shed my skin ALL the time so why dont my tatoos eventually just disappear all together as the years go by????

  7. So I started having to squint when looking at far writing. This started about a month ago, I could see perfectly before that. Any reasons? I am 17 years old.

  8. Why when air is sped up and blown, like from a fan for instance or the wind, it becomes cool or cooler than it was when it was calm?

  9. Here's something I've always wondered, when opening a can of SpaghetttiO's with meatballs why does more of the contents of the can come out when opening the can from the bottom than the top?

  10. Squinting does not help me to see better. It never has. I can squint with all my effort at something and it does not make any noticeable difference in the clarity of it.

  11. Way off.  Squinting makes your eye more like a "pin-hole camera".  The effectively reduced iris from squinting increases the depth of field of what you are focused on, thus bringing more things into focus.

  12. Here's a question: Why aren't you woken up by the sound of your own snoring?

    When my wife gets a cold, her snoring literally sounds like sawing timber. However, when I quietly open a drawer in my bedside table, pick up my little box with earplugs and open it, she wakes up, being annoyed that I woke her. How come these tiny noises wake her up when her snoring, which is much louder, doesn't?

  13. I have 20-10 vision normally, and i actually see better by widening my eyes. Squinting results in blurry or even double vision.

  14. Über facts is definitly watching these videos and turning them into new uber facts. For weeks now i will watch a new mental floss video and then withon the next 24 hours there is an uber fact about it. It really bothers me

  15. @anders lundin thats easy its like if u rub ur nails on a chalk board if ur makeing the noise its not so bad to only u

  16. I would have thought that it works for the same reason that increasing the aperture in a camera makes things sharper. It increases the depth of field.

  17. Hey Craig, i think an important point you didn't mention was "depth of field'. Our eyes work the same way as a camera, hence, as the aperture reduces in size (the size of the iris hole), inversely, the amount of subject in focus increases. Im positive there's a more eloquent way of putting it, so, yeah, help me out. Love your work.

  18. Why can't you sleep with your eyes open

    If you blink reflexively why can't you just fall asleep and still blinking

  19. OMG! I have that same sweater! And I never thought of using the brown t-shirt underneath as an accent! Oh, and all that eye stuff was cool, too.

  20. I had to read this title 3 times cause I thought it was a mistake. Some people see better? I see a blurry mess of eyelashes, eyelids and less light. I'd never even think to squint if I was trying to see detail… Is there something wrong with me, or are there lots of us who see worse when squinting?

  21. This really shows that you guys didn't do much homework learning this topic. please do better research for the viewers that are not science savvy

  22. Potential question for an upcoming show: Why are all creative works and characters created before 1923 in the public domain?

  23. Explain sunburns! Every science-based channel has covered what the sun causes in terms of damage to the epidermis, but not how the body reacts.
    I want to know the details of how the veins are signalled to dilate, how that release of heat via the blood should be managed (as in is it a good or bad idea to put moisturizer on a burn), and why is it necessary to deliver more blood to those areas (is it the need to bring in leukocytes or otherwise). All is see is cancer, cancer, cancer explained in the other sunburn vids. I would like to know more about thymine dimers too and how they are repaired – not the result of too many mistakes in DNA to cause mutation.

  24. How do cuts in the mouth, such as a bit tongue, or a split lip, stop bleeding, since scabs don't/can't form?

  25. question 1-so do asian people see better than everyone else since their eyes are already kind of shaped like that?
    and question 2- was that previous question racist?

  26. Squinting narrows the effective aperture, which widens the depth of field, increasing the range of focus regardless of whether the lens is correctly focused or not.  This also explains why people over 45 (those with presbyopia) can focus on close objects far better in bright light.  The pupil is narrowed, which also reduces aperture.  No squinting required. 

    An even better example – try holding a smartphone or tablet screen extremely close to your eye (2 inches or so).  You should be unable to focus properly on something so close.  Now, interpose a pinhole (you can form one in the crook of a bent finger).  This will reduce the aperture dramatically, bringing virtually everything into focus.  Done properly, you should be able to see the screen in perfect clarity, again without squinting. A smartphone screen makes a great example because it is self-illuminated.

  27. Here's another eyesight-related question: Would your eyesight get worse if you constantly wear glasses? (for those that don't NEED to wear them)

  28. I want to know how much water something needs to have to expand when it freezes. Does it need to be more than 50% water?

    Also, what evolutionary advantage would high arches on feet provided?

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