The retina of our eye is composed of light sensitive cells. Light sensitive cells are of two types namely, rods and cones. There are three types of cones., those that are stimulated by low frequencies, those stimulated by intermediate frequencies and those stimulated by higher frequency visible light. The rods are found near the periphery of the retina while the three types of cones are found in and around the yellow spot (the point of acutest or sharpest vision in the retina).
Cones are responsible for color vision. Hence we mostly see color by focusing an image on the yellow spot where there are no rods. In the human eye, the number of cones gradually decreases away from the yellow spot.
Rods help to view objects in darkness whereas cones help to view objects in bright light.
