Photoreceptors are responsible for visual phototransduction. They convert light into biological signals. In humans, rods, cone, and retinal ganglion cells are the 3 main photoreceptors. Rods are narrow and are present throughout the retina. They are very sensitive, They can be triggered by a single photon also. They are responsible for the visuals we get in the low-light conditions. Cons need a high number of photons, in order to produce signals. They are responsible for visualization of colors. Rhodopsin is the pigment molecule of the rod cells. It is very sensitive to the light, and enables visualization in dim lights.
There are currently three known types of photo receptor cells in mammalian eyes: rods, cones, and photosensitive retinal ganglion cells. The two classic photo receptor cells are rods and cones, each contributing information used by the visual system to form a representation of the visual world, sight.
