(a) Cones are central to our ability to see colour. Cones help people see colours and have depth perception. Cones are located in the central fovea (central area of the retina). They are less sensitive than rods and require bright lighting.
(b) Rods are highly sensitive cells located in the outer area of the retina (the lining of the back of the eye). They are used in areas of dim light and are most acute to light, shape and movement changes. Rods do not detect colour. Rods help people to see in low light.