Rods are receptor cells
in an elongated shape that cover the entire surface of the retina. They constitute, with cones, the photosensitive cells of the retina. These cells have the role of transforming the electromagnetic impulse of light received by the eye into a bioelectric impulse. This impulse is then sent to the brain, which interprets it and develops vision. Colors are not perceived by the photoreceptor cells of the rods. However, it is they that detect movements and permit scotopic vision (in low light conditions).