Why does squinting improve my vision when I dont’ have my contacts in or glasses on?
It tends to make the eye rounder which is what caused the distorted vision in the first place.
I like that a guy named Bongmaster explains distorted vision…funny
I have heard this explanation before although I have never seen any evidence to back it up. I am not at all convinced that squinting applies pressure in such a way as to reshape the eyeball. I must disagree, though IANAO. I think this is more of a phenomenon of optics. Squinting is like stopping down a camera lens. The smaller the diaphragm, the greater the depth of field because the farther from the center of the lens the light enters, the more exagerrated its out-of-focusness will be. You can try this by punching a small hole in a piece of paper and looking through that instead of squinting, eliminating the possibility that this is due to any shape in the eye. A document at www.phy.olemiss.edu/~thomas/weblab/ 224_web_items/Exp26_EyeModel.pdf explains this rather well.
Whoops, extra space. Try this link.
Not an ophthalmologist, but I’ve got a degree in optics. Cooking with Gas has it right. If you want to verify this, try looking through a small hole punched in something (a hole in a watchband works well). Stopping down the system with a smaller aperture means that the aberrations from off-axis rays are eliminated, but it’s at the ciost of the amount of lighht you get – the image is better, but dimmer. A few years ago somebody actually sold “eyeglasses” that worked on this principle.