The utilization of the bodys visual system, which includes the eyes and the brain as well, helps a person understand the things that he sees. Likely, the matter is more important in terms of explaining why a certain thing appears as it does and how the said aspects of visualization affect the meaning of things as they appear to the eyes. As for example, a tree may appear to be just a tree to a person in one look.
While on the other hand, if the person examines the entire picture as it appears to his eyes, the picture may have a different effect to the person as it may sense an aura of relaxation and calmness that may bring a particular rest in the mind of a person. Likely, this perception is an inner description of what the eyes see as per described through the interpretation of the brain in connection to what the eyes see. In terms of the color spectrum, as the eyes see the rainbow to have different colors when actually the eyes could only recognize three colors, why is this so?
The utilization of eyes photo receptors makes it easier for the eyes to see the prism in a more complex collection of colors that produce the rainbows image in the mind. From this particular example, it could be understood that human vision does not only rely on what is actually seen but on what is understood by the brain as the eyes function as the mirror to the things that it sees.
Nigel W. Daw (17 November 1967). Goldfish Retina: Organization for Simultaneous Color Contrast. Science 158 (3803): 942944.Bevil R. Conway (2002). Neural Mechanisms of Color Vision: Double-Opponent Cells in the Visual Cortex. Springer. ISBN 1402070926. Conway, Bevil R (2001). Spatial structure of cone inputs to color cells in alert macaque primary visual cortex (V-1) Journal of Neuroscience. 21 (8), 2768-2783. John E. Dowling (2001). Neurons and Networks: An Introduction to Behavioral Neuroscience. Harvard University Press. ISBN 0674004620. McCann, M. , ed. 1993. Edwin H. Lands Essays. Springfield, Va. : Society for Imaging Science and Technology.