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The Vision Process

"Vision," says neuroscientist William Newsome, "happens in the brain, not the eye (Siegfried 1)."Although light enters the body through the eye, the majority of the processing takes place in the brain.A full quarter of the cerebral cortex is devoted to sight (Brownlee 1).Light is received through the eye as electromagnetic energy.What we see as visible light is only a small portion of the whole spectrum of electromagnetic radiation.This paper will be a map of how the vision process works.
The cornea and sclera make up the outer part of the eye.They hold the eye together and strengthen it.The sclera covers nearly five-sixths of the eye and the cornea takes up only one-sixth.The sclera is the white part of the eye.The cornea allows light to enter the eye.
The uveal tract is the middle layer of the eye.It is made up of three parts.From to back, they are: (1) the iris, (2) the ciliary body, and (3) the choroid.
The iris is the colored part of the eye.It lies behind the cornea.The iris controls the size of the pupil opening.At the center of the iris is the pupil.The pupil is the black circle in the middle of the eye.The size of the pupil determines how much light enters the eye.There are two muscles in the iris that automatically change the size of the pupil depending on how much light is present.In low light, the dilator muscle opens up the pupil so as much light as possible can enter the eye.In bright light, the sphincter muscle closes the pupil to keep too much light from entering.The pupil also closes when focusing on a nearby object.
The ciliary body surrounds the iris.It's connected by strong fibers to the lens, which is right behind the iris.The lens is flexible and about the size and shape of an aspirin tablet.The muscles of ciliary body constantly change the shape of the lens.These changes make a sharp visual image all the time as the eye changes focu…

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