The Process Of Sight

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The eye is a complex and amazing organ filled with nerves, lenses, liquid, and more. The eye and the brain work together to give us the sensation of sight. The cornea, iris, pupil, lens, vitreous, retina, fovea, and the optic nerve are all part of the eye. They all play a role in the process of sight. Light rays reflected from an object are focused by the cornea and the lens. These light rays then pass through the vitreous and produce an upside-down image of the object on the light sensitive retina. The retina then converts the image into electric impulses that are carried by the optic nerve to the brain’s visual cortex, where they produce the sensation of sight. The optic nerve from each eye merge at the optic chiasm. Axon fibers from the nasal retina of each eye cross to the opposite side of the chiasm, while axon fibers from the temporal retina of each eye continue on the same side. The realigned axons emerge from the chiasm as the left and right optic tracts, ending in the left and right lateral geniculate bodies. From there the axons connect to the optic radiations, which travel to the right and left halves of the visual cortex of the brain. We all also have a blind spot. This blind spot is a small portion of the visual field of each eye that corresponds to the position of the optic nerve. There are no photoreceptors in the optic nerve, therefore, there is no image detection in this area. The blind spot of the right eye is located to the right of the center of vision and vice versa in the left eye. With both eyes open, the blind spots are not perceived because the visual fields of both eyes overlap. Even with one eye closed, the blind spot can be difficult to detect because of the ability of the brain to “fill in” or ignore the missing portion of the image. For those individuals who are fortunate to have sight can agree that our eyes are very useful in our
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