The retina is the extension of the central nervous system that senses light. Cones and rods, situated in the outer retina, convert light into electrical signals that travel through intermediate neurons where these are further processed until they finally reach retinal ganglion cells (RGCs). The afferent neurons of the retina, the RGCs, send the visual information through their axons in the optic nerve to the ret-inorecipient nuclei in the brain, where is further analysed.