how+the+eye+detects+color,+Never+gonna+give+you+up,+never+gonna+let+you+down.+never+gonna+tell+a+lie+and+hurt+you.

In the human eye, light enters the pupil and is focused on the retina by the lens. Light-sensitive nerve cells called rods(for brightness) and cones (for color) react to the light. They interact with each other and send messages to the brain that indicate brightness, color, and contour.

Color Blindness

 * Although defective color vision may be acquired as a result of another eye disorder, the vast majority of color blind cases are hereditary - present at birth. The gene for this is carried in the X chromosome. Since males have an X-Y pairing and females have X-X, color blindness can occur much more easily in males and is typically passed to them by their mothers.
 * Color blindness is rooted in the chromosomal differences between males and females. Females may be carriers of color blindness, but males are more commonly affected.