Coloured scanning electron micrograph (SEM) of a resin cast of the retina. Blood vessels (red, purple) radiate out from the optic disc (yellow). The optic disc is the area where the optic nerve and blood vessels enter the eye.
Scanning electron micrograph of rods and cones in the eye. Rods are long nerve cells which respond to dim light, enabling images to be detected. Cones are shorter cells which detect color. Rods and cones pass visual signals through the optic nerve to the