<p>Light-sensitive sensory cells that convert light quanta (photons) into electrical signals of the nervous system. The photoreceptors in the retina of the eye are called cones, rods and ganglion cells containing melanopsin. The cones are responsible for color vision. Their highest density is in the eye center, the so-called yellow spot. Here is the area of the retina that provides the highest spatial resolution. The rods are responsible for seeing light and dark and have a higher sensitivity than the cones. They are therefore important for vision at night. They are mainly found in the outer region of the visual field. The ganglion cells containing melanopsin are not considered visual cells, because they don't transmit a picture to the central nervous system, but only brightness information to control the body clock.</p>