Pins & Eyeballs

November 29, 2012

Eva Gusnowski

Eyes are very interesting and very complex organs; mine also happen to be extremely challenged. Having been bespectacled for a number of years now, I’ve always found it interesting (and enraging) as to how other people have perfect vision, whereas mine refuse to see anything clearly that isn’t threatening to suffocate me.

Here are the simplified basics as to how the eye works:

At the front of the eye is the cornea and lens. These work to bend rays of light so that they converge on the back of the eye where the retina lies. When the rays of light come together at the retina, a clear image of that object is formed. However, in many unfortunate individuals (myself included) the rays of light do not converge at the retina because they are bent too much or not enough. Instead, the beams cross in front of the retina leading to a blurry image of faraway objects (leading to nearsightedness) or the beams will cross behind the retina leading to a blurry image of nearby objects (leading to farsightedness).




The pinhole effect is a way to (at least partially) prevent blurry images from forming. The way this is achieved is by limiting the amount of light rays that are able to enter the eye via a small pinhole. In this way, the light is able to hit the retina more directly, thereby rendering a much clearer image. Don’t believe me? Try it for yourself…

…look at this picture from a distance with one eye closed:


…now make your hand into a very small pinhole like this:



…now look through the pinhole at the picture and see how much clearer it actually is! Now you always have some built-in binoculars with you so you can get a better look at the bus number that’s coming down the road.

It’s crazy how such a simple pinhole works so well to improve vision, and the readers of Science in Seconds aren’t the only ones who know this little secret. Even nature has figured this one out (as it usually does). The pinhole eye is seen in chambered nautiluses, a species that has developed this eye form in order to allow the maximum resolution from an eye that does not contain a lens.


Because it just ain't a party 'til you're wearing your hands as glasses.



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