From a previous ELI5, I know that squinting helps you see better because you flex your cornea which helps bend the light to get a better focal point, but shouldn’t squinting when you have your glasses on/contacts in cause an overcorrection as if you are wearing an overprescribed pair of glasses/contacts?
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>I know that squinting helps you see better because you flex your cornea which helps bend the light to get a better focal point.
This isn’t accurate. Squinting helps you focus because it reduces the size of the hole light has to get through to reach your retina. The same way a camera obscura works, or why reducing the aperture of a camera increases the depth of field.
This is also one reason you can focus better in bright light, your pupil is smaller.
It won’t make a difference, when you squint without correction, you are only allowing tiny amounts of light which are travelling almost perpendicular to the lens of your eye so correction isn’t needed . When you are wearing glasses it is already corrected and when you do squint the you will allow the same amount of rays to pass through but they are already perpendicular which means they don’t need to be corrected because perpendicular rays to the lens don’t change direction.
I assume it’s for the same reasons we can do a camera obscura
[Here is the video](https://www.youtube.com/watch?v=qIp9kItDUh8) by Physics Girl about the Pinhole Camera/ Camera Obscura.
And here is the[same video but skipped to the explanation](https://youtu.be/qIp9kItDUh8?t=232).
Basically when the hole letting the light in is wide open, it is taking in light/images from every possible angle. When the whole closes more, it sorta acts as a filter by limiting the angles that these “beams” of light can come in at to hit any given point. The more closed a hole is, the less beams of light from different angles will hit any given location of your retina, sorta focusing your image.
I never learned this directly, so take my explanation with a grain of salt.. but totally watch the video anyway cuz i think they’re fun
Many people have a football shaped lens or cornea. This is named “astigmatism”. Light focuses at different distances and becomes blurred. This may be in addition to lenses that are too strong or eyes that are too long or too short. By reducing the pupil size with squinting or making a small hole in your hand and looking through it, you use just the round center section. This also increases the focal distance such as looking in a pinhole camera. Every persons eyes are different and there are many combinations. Most eyes are similar left to right. But many are not.
My eyes are unusual. I have astigmatism in one eye in the lens. One eye has it in the cornea. it’s effect is the same. Most who have astigmatism have both of the long axes of the football shape parallel. Like || or =. I have this pattern /. Almost as if they are tilted. I have many other unusual features where I see the center of one eye like a donut hole and the donut ring of the other. I finally found an eye doctor that has the same condition who explained to me after 50 years the odd things I see that few get to experience. Src. my ophthalmologist.
You see better when you squint because you deform your eyes.
For People who are short sited, the sharpest picture of the outside world falls just in front of the retina, creating a blurred picture. When you squint, you squash your eyes and change the shape. If you are lucky you change the shape of your eye in a way that will focus the picture on your retina creating a sharper image.
You can’t change the size of your pupil (the black hole in the middle of the eye) with squinting. However there is a reflex where when you focus on something nearby your pupils get smaller, to help focus nearby which would be a similar idea to the camera obscura.
No one has gotten it right here yet.
The lens is the most important part of the eye, next to the retina that is. People have a hard time focusing on things simply because the lens is not properly aligned. Light comes into the lens and HAS TO CONVERGE onto the retina, hence we’re all actually seeing an upside down image of the world our brains just flip it.
What has this got to do with squinting? We’ll, the focal point of the lens has to be perfectly placed so that it hits the retina, if it converges too early you become short sighted, if it converges after the retina then you become long sighted.
What you are doing by squinting is applying pressure to the iris causing the lens to compress hence changing the focal point. Glasses also help by changing the focal point so that light hits the retina.
People on here talking about smaller rays of light have no clue what they’re on about lmao
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