The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the mammalian eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth. The human eye can distinguish about 10 million colors.
In common with the eyes of other mammals, the human eye's non-image-forming photosensitive ganglion cells in the retina receive the light signals which affect adjustment of the size of the pupil, regulation and suppression of the hormone melatonin and entrainment of the body clock.
Read more about Human Eye: General Properties, Dynamic Range, Field of View, Eye Irritation, Eye Movement, Near Response, Effects of Aging, Eye Care Professionals
Famous quotes containing the words human and/or eye:
“The only thing that one really knows about human nature is that it changes. Change is the one quality we can predicate of it. The systems that fail are those that rely on the permanency of human nature, and not on its growth and development. The error of Louis XIV was that he thought human nature would always be the same. The result of his error was the French Revolution. It was an admirable result.”
—Oscar Wilde (1854–1900)
“Often on bare rocky carries the trail was so indistinct that I repeatedly lost it, but when I walked behind him I observed that he could keep it almost like a hound, and rarely hesitated, or, if he paused a moment on a bare rock, his eye immediately detected some sign which would have escaped me. Frequently we found no path at all at these places, and were to him unaccountably delayed. He would only say it was “ver strange.””
—Henry David Thoreau (1817–1862)