Fundus camera image of the retina of a normal eye, showing the distribution of the retinal veins & arteries: the central retinal artery (a branch of the opthalmic artery) enters the optic nerve 2 cm before it reaches the eyeball, emerging through the retina in the centre of the optic disc (the blind spot of the eye, the pale area on the left). The dark oval region free of large blood vessels (right) is the macula, in the centre of which the fovea is found. The fovea is the region with highest visual acuity. An extension of the optic nerve, the retina consists of photosensitive cells (rods & cones) which translate light energy into nervous impulses.