The neuronal elements of the retina are not themselves light sensitive, but transmit impulses generated when light hits the photoreceptors. The outer segment is connected by a cilium to an inner segment which contains a nucleus. Rods are about 500 times more sensitive to light than cones , but cones give us colour vision. The rod disks are separated from each other and from the outer segment membrane by cytoplasm. The lamellae in cones are formed from one continuous folded surface, rather than separate disks, as is found in the rods.
Cones synapse with horizontal and bipolar cells via flattened oval end-bulbs, called cone pedicules.
The outer segments of cones contain one of three different photopigments which can absorb light of long, medium or short wavelengths respectively, thus providing us with colour vision. The fovea lies slightly below and to one side of the optic disk. The cones here have individual connections with the bipolar and ganglion cells, hence the fovea gives us our most sensitive and acute vision. This is the point at which axons leave the eyeball and join the optic nerve. Also, arteries enter and veins leave the retina at the optic disk.