The eye is the most sophisticated and most sensible organ of the human body. It is the most important human sense, because the eye is receiving 90% of the information from the environment. It acts like a camera, because of the light that bounces off the items reflects to the cornea, passes through the pupil, adapts and then falls on the retina of the eye. There are two types of photoreceptors: rods that register light and cones that register color. The light is transferred to the vision center located in the back of the brain. Here, the received electrical impulses are converted into visual images. Interestingly, each eye to the brain brings different picture and yet the brain manages to merge into a single image.
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This complex organ is composed of several parts, which with a proper function allow real picture.
- Cornea - the first of the eye through which the light enters. Its task is to perform a breach of light's rays because it has the greatest power to bend. The curve is different, the front side is more convex while the rear side is more concave. It consists of 5 different layers and contains a huge number of nerves and because of this is the most sensible tissue in the body.
- Retina - is the most important functional part of the eye because the application converts light into electrical impulses which are then sent to the brain thus forming a visual image.
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Iris - is the colored part of the eye. Its task is to change the size of the pupil. In bright light, the iris narrows and thus prevents touching too strong light in the eye. When viewing in the dark, the iris spread thus enabling a better perception.
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Pupila - a circular hole in the center of iris. It has a black color because it is seen through the internal pigmented layer of the retina.
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Sclera - a white part of the eye, or hard, opaque eye cover, designed to protect the structure of the eye. Covers 5/6 of the eyeballs and it is connected to six eye muscles that allow movement of the eye.
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Eye lens (lens cristallina) - a transparent, biconvex structure (because both surfaces protrude forward). Over the years the eye lens loses its flexibility and consequently appears presbiopija while in loss of transparency appears cataracts (lens blur).
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Optic nerve (nervus opticus) - It consists of nerve fibers that extend from receptors in the retina of the eye and extend to the center of vision. Its task is to conduct electrical impulses produced by the light in the retina to the vision center.