Central retinal artery

At a glance

English

Central retinal artery

Latin (TA2)

Arteria centralis retinae

System

Artery

Region

Head

Side

Paired, left and right

About the central retinal artery

The central retinal artery is a fine vessel, about 0.16 mm across, and one of the first branches of the ophthalmic artery after that artery enters the orbit. It runs forwards below the optic nerve, then pierces the nerve's dural sheath and enters the nerve itself about 1 cm behind the eyeball. It continues forwards in the core of the nerve to the optic disc, where it appears in the centre of the disc on examination of the fundus.

At the disc the artery divides into superior and inferior branches, each of which splits again into nasal and temporal branches. These spread over the inner surface of the retina in the nerve fibre layer, forming the vessels seen with an ophthalmoscope. The arteries are end arteries: they do not join one another, so each supplies its own sector of retina. They nourish the inner layers, including the ganglion cells and the nerve fibres that pass back into the optic nerve towards the lateral geniculate body of the thalamus. The outer layers, with the rods and cones, are fed by diffusion from the choroid instead.

The fovea, the small pit at the centre of the macula on which light is focused for sharp vision, has no retinal vessels at all and depends entirely on the choroid. In roughly a fifth of people a cilioretinal artery, coming from the short posterior ciliary arteries, also supplies a strip of retina between the disc and the macula. The central retinal artery is the persisting stem of the embryo's hyaloid artery, whose forward part disappears and leaves the hyaloid canal through the vitreous.

Sudden blockage of the central retinal artery, usually by an embolus, causes abrupt painless loss of sight in the affected eye. The retina turns pale and swollen, while the fovea, still nourished from the choroid, stands out as a cherry-red spot. If a cilioretinal artery is present, central vision may be kept. Blockage of one branch causes loss of only part of the visual field. The vessels can be studied with fluorescein angiography.

Course and supply

Arises from

Arises from the ophthalmic artery in the orbit, close to the optic canal.

Ends in

Divides at the optic disc into superior and inferior branches, each with nasal and temporal divisions, that end within the retina.

Supplies

Supplies the inner layers of the retina, including the ganglion cells and nerve fibres, and the front part of the optic nerve; the fovea is not supplied.