This might sound a little far out, but hang with me.
I am pretty sure that the reason that I can see better when I squint is because I am squeezing my eyeball, physically deforming it, to my eyes’ advantage. The squeeze causes the lense on one end to be a better distance from the receptor at the other end.
Assuming this " lense/receptor distance from each other thing" is true, my question is: Does sleeping on my eyeballs all night every night cause me any long term negative deformation to my eyes, causing the lense/receptor distance to change, causing eyesight to suffer?
I know when I wake from sleeping directly on one of my eyes, my vision in that eye is very blurry for the next couple seconds. I ALWAYS sleep on the side of my head.
It’s pretty hard to “sleep on your eyeballs” in the sense that most people have slight projections above and below the eye. That is, most people could place a flat hand against their face, covering their eye, without putting much pressure on the eyeball.
If you were putting enough pressure on your eye that the orb was badly deformed, or deprived of oxygen, it would be quite painful. IANAED, but I doubt it would make a long term difference unless you are able to genuinely “sleep on your eyeball”, which is not the same as sleeping on teh side of your face.
i think its for a different reason, but this is just from experience.
i have sh!tty vision… my contacts are -6.0 and -5.5… in any case, squinting makes me see better w/o the contacts in… i think its because of the small hole you look through compared to the normal open eye… to test this curl your pointer finger into your hand like you were gonna make a fist, make it very tight so there is just a TINY hole… now watch tv through that hole and if you have bad vision, you should be able to see very well compared to what you would normally see. with that said i am near sighted, it might not work if you are far sighted. i read something once that said why this works, something about the small hole and kind of how it works as a lens, kind of like how pinhole cameras work… but i have no idea where i read it.
One other option may be that by simply limiting the amount of the lens used, you avoid aberations around the edges.
The middle of your lens has better optic qualities than the outer. The further out towards the edge you go, the worse of the optics get. By allowing light to pass through the outer egdes of the system, it will screw up the otherwize clear images from from the middle of the lens.
This is the reason that when reading in a dark room, it may seem as though there is enough light to see the page and letters, but you can’t actually read the letters. In the dark, your pupils dialate to let in more light. By dialating though, it allows light to pass through the outer edges of the lens, which distorts the image so badly, you can’t read.
Squinting your eyes may just be blocking some of the light that would otherwise pass through the egdes of the lens, same thing with looking through a tiny hole perhaps, although the pin hole camera idea also has merit.
We just covered lenses in my physics class, so I better get this right.
When you squint, you’re changing the way the light rays are hitting the lens of your eye, bending them, etc. This in itself can act like a lens (just in terms of altering the path of the light rays before they hit your eye). In terms of near-sightedness, the problem is that the light converges at a point in front of where it should (the back of the eyeball, I believe). A diverging lens extends this point to where it should be. I would assume that squinting (or looking through a tiny hole) bends the light in a fashion that makes the light converge closer to where it should, ideally.
Holes don’t bend the light (diffraction notwithstanding, but we’ll ignore that), but a small hole will only permit light to pass through in a straight line; so each ray of light from each part of the subject has only one possible path to a specific spot on the retina.
Part of the reason we see better when the light is bright (apart from the greater stimulation) is that the pupil closes up and the eye behaves more like a pinhole camera, relying less on the focusing action of the lens.
Also not to be underestimated is the effect of fluid on the surface of the eye; when you close your eyes up to just a tiny crack, it’s hard to see out because you’re looking through a thicker film of water (wiped into one place by your closing eyelids and held there by surface tension/capilliary action.
[sidetrack]I’m long sighted and I can get my eyesight to transiently improve by hanging my head, looking directly downwards and trying not to blink; the fluids from my tear ducts collect on the lowest part of my eyeball (which, in this position, happens to be the part I’m looking out of) and begin to form a ‘drip’ (hanging down slightly from the surface of my eye).
This forms a crude lens and it can markedly improve my vision. Not terribly practical though.
