This does not necessarily holds for people wearing glasses,...
but looking far away, or not necessarily far away for those ones with the glasses...when removing the glasses and putting their hands in from of the eye and just looking through a little-little hole, formed by 2 fingers keeping close... they just see much-much sharper as normally....
2006-08-02 00:32:09 · 14 answers · asked by Marian 1 in Science & Mathematics ➔ Physics
Normally, the light which strikes the retina can come from any point on the lens at the front of the eye, and if the lens isn't optically perfect (which of course it isn't), then there will be variation across the lens in where the light gets focussed on the retina, and that's what we perceive as a blurred image. The worse the lens is, the more the blurring (because the light from each point gets scattered over a wider area of the retina).
If you look through a hole that is *smaller* than the area of the lens, then not all of the lens can contribute to the image on the retina, so there is less chance of blurring (each point you're looking at gets scattered over a smaller area of the retina), and therefore a sharper image.
Incidentally this is why our eyesight is sharper in bright light - the iris contracts so that the hole in the middle is smaller than the lens, and we see a sharper image for the same reason that we see a sharper image looking through a small hole, as in your question. When the light is dim, the iris has to be wide open to allow in more light, and vision tends to be more blurred.
2006-08-02 00:52:22 · answer #1 · answered by Anonymous · 0⤊ 0⤋
B-cause it allows only a narrow pencil of parallel rays to pass through the eye-lens producing sharper focused image as per laws of optical science.
2006-08-02 00:51:57 · answer #2 · answered by desh 1 · 0⤊ 0⤋
The small hole is causing the light to focus like a lens. It is like a pin hole camera focuses light on the film.
2006-08-02 01:21:14 · answer #3 · answered by science teacher 7 · 0⤊ 0⤋
light is distorted when people have bad eyes. Looking through a smaller opening focuses the light threw a tiny hole and transfers it to the retina.
2006-08-02 00:36:34 · answer #4 · answered by Anonymous · 0⤊ 0⤋
Because you are taking away from peripheral vision allowing your eyes to focus on a smaller more defined point.
2006-08-02 00:37:04 · answer #5 · answered by wild_orchid_1988 3 · 0⤊ 0⤋
All light rays are focussed on macula of retina which is the most sensitive part of retina.Other disturbing light is avoided from narrow aperture.
2006-08-02 01:40:08 · answer #6 · answered by J.SWAMY I ఇ జ స్వామి 7 · 0⤊ 0⤋
I think it might be because our vision is concentrated on one sight, and rather than being distractd by various bright interfering colors, your eye sees everything within a rim of black ,which makes your vision concentrate on a certain point more.
2006-08-02 00:43:49 · answer #7 · answered by sweateredpanda 4 · 0⤊ 0⤋
Because your forcing our eyes to focus on a much narrower area.. Same way you can see better when you squint
2006-08-02 00:36:46 · answer #8 · answered by Anonymous · 0⤊ 0⤋
its because it blocks out all the other bright and distracting things from what you want to view. so more sharper veiwage
2006-08-02 00:37:01 · answer #9 · answered by voodoochild 4 · 0⤊ 0⤋
I believe it is because your eyes naturally focus harder in the area of vission.
2006-08-02 00:37:40 · answer #10 · answered by therealhumantorch 3 · 0⤊ 0⤋