There is disagreement as to whether or not this constitutes one, two or even three distinct senses. Some people make a distinction between "black and white" vision and the perception of color, and others point out that rod vision[?] uses different physical detectors on the retina from cone vision[?]. Some argue that the perception of depth also constitutes a sense, but others argue that this is really a cognitive[?] (that is, post-sensory) function derived from having stereoscopic vision (two eyes) and is not a sensory perception as such.
The eye is the light-sensitive organ that performs the first stages of vision. The eye's retina performs the first stages of visual perception processing, with the remaining stages of visual perception occuring in the optic nerve and the visual cortex of the brain.
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