How Does the Human Eye Perceive Color?
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Pathology of the Eye
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Our eyes are filled with mechanisms, each with simple but important functions, that enable us to experience sight. The first step in seeing our environment comes from light. When light is reflected off of an object, the light enters the eye through the pupil and is flipped upside down by a clear lens that is just behind the iris. The image is then projected through the body of the eye (known as the corpus viktrum) and onto the retina--the main stage for where color vision is generated.
Rods and Cones
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The retina in the human eye contains two types of vision cells, or photoreceptors: rods and cones. Rods are long, cylindrical cells that allow for night vision and the sight of general shapes and forms.
The cone photoreceptors are responsible for daytime vision, color vision and the finer details of the things we look at. Cones are activated by a certain amount and spectrum of light, which is why we don't see colors in the dark. Despite the fact that cones seem to provide our most important aspects of sight, in the human eye, rods outnumber cones. -
From Light to Color
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When an image enters the eye in the form of light and is projected onto the surface of the retina, an entire series of chemical reactions takes place. The light signals travel through the cells on the surface of the retina and flow down into the rods and cones.
The cones can distinguish color from the frequency of the light being reflected off of the viewed object. Each color has its own unique wavelength. The color with the shortest wavelength is violet, while the longest wavelength belongs to red.
The rods and cones convert the light wavelengths into electrical signals. The photoreceptors then send the signals down through cells below them that lead to the optic nerve. The optic nerve sends the electrical impulses into the brain, where the signals are translated into what we perceive as sight.
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