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Human Eye

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Submitted By arindambarua
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You should never take your eyes for granted; don't wait until you have a problem to have a vision exam. You should have your eyes checked annually.
The eye is very delicate and in order to see well, all parts must be able to function properly. Always try to protect your eyes. Did you know that the bones in your head protect your eyes from injury; even the eyelids close out unwanted light and also dirt. Your tears from nearby tear ducts work hard to keep the eye's surface moist and clean.
The eye is filled with a clear jelly in its center called the vitreous humor. Three layers of tissue surround the vitreous humor. There is an outer layer, which has tough tissues and protects the eye; then there is a middle layer with a network of blood vessels that give nourishment to the eye. An inner layer contains cells sensitive to light that enable you to see. The whites of your eyes are the sclera, which is a tough, fibrous tissue. The cornea is the bulge in the front center of the eye that serves as a window to let light into the other layers of the eye. There is a thin layer of tears that gives the cornea smoothness to be crystal clear. The conjunctive is a clear membrane that lines the insides of the eyelid and also covers the front of the eye around the cornea.
The pupil is a round opening surrounded by muscles that regulate the amount of light that enters the eye; pupils will enlarge if the light is too dim and if the light is too bright, pupils become small to keep out too much light. The iris controls the size of the pupil and is a colored circle containing many muscles. It can appear gray, green, blue, or brown. The muscles in the iris receive their nourishment from blood vessels in the middle layer of eye tissuethat contains many blood vessels; this tissue is the choroid. There is a lens behind the pupil suspended by the middle layer of the eye, and it is a

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