The ophthalmic artery originates from the distal end of the internal carotid artery (ICA). After several microscopic branches emerge from the ICA in the petrous region, the ophthalmic artery proceeds toward the globe. After the origin of the ophthalmic artery, the ICA gives off the anterior choroidal and posterior communicating arteries.
As the ophthalmic artery traverses the optic nerve, it gives off the central retinal artery and, more distally, the posterior ciliary arteries. The posterior one third of the optic nerve is supplied by penetrating arteries from the anterior communicating and anterior cerebral arteries. The anterior two thirds are supplied by the central retinal artery, which lies deep inside the optic nerve; the posterior ciliary arteries supply the peripheral nerve substance. A watershed area is delineated near the head of the optic nerve between the posterior ciliary artery and the central retinal artery.
For more information, see Medscape’s Resource Center, Neuro-ophthalmology.
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