Blood supply of the retina and choroid
- Anatomy and physiology
The central retinal artery feeds the inner retina; the ciliary arteries feed the choroid and optic nerve head. Each fails in its own way.
See it in 3D: Ophthalmic artery · Central retinal artery · Ophthalmic veins · Choroid · Retina
What it is
The ophthalmic artery, the first branch of the internal carotid, gives two separate supplies. The central retinal artery enters the optic nerve and branches over the inner retina; its branches are end arteries. The posterior ciliary arteries supply the choroid, which feeds the photoreceptors, and the optic nerve head. Which supply fails explains the picture of artery occlusions and ischaemic optic neuropathy.
Clinical anatomy
- Ophthalmic artery: first intracranial branch of the internal carotid artery, entering the orbit through the optic canal.
- Central retinal artery: enters the optic nerve behind the eye and divides at the disc into four main branches.
- Posterior ciliary arteries: short ones to the choroid and optic nerve head, long ones to the front of the eye.
- Cilioretinal artery: a branch from the ciliary circulation that supplies part of the macula in a minority of eyes.
- Central retinal vein: drains to the superior ophthalmic vein and the cavernous sinus.
Physiology
- Retinal vessels have tight junctions (blood-retinal barrier) and autoregulate their flow.
- The choroid has very high flow and supplies most of the oxygen used by the photoreceptors.
- The retina is the only place where arterioles and venules can be seen directly, which makes it a window on systemic disease.
Clinical correlation
- Central retinal artery occlusion infarcts the inner retina; an eye with a cilioretinal artery may keep central vision.
- Occlusion of the posterior ciliary arteries (giant cell arteritis) infarcts the optic nerve head: ischaemic optic neuropathy.
- Emboli usually come from the carotid artery or the heart.
- Hypertension and diabetes are seen in the retinal vessels: arteriolar narrowing, nicking, haemorrhages, cotton-wool spots.
Next step / Initial management
- Sudden painless visual loss: same-day assessment, stroke pathway for artery occlusion.
- Visible retinal embolus or vascular occlusion: carotid imaging, ECG and cardiovascular risk assessment.
- Retinal vascular signs of hypertension or diabetes: assess and treat the systemic disease, and refer according to severity.
- Over 50 with ischaemic optic neuropathy: ESR and CRP for giant cell arteritis.
Test yourself
Think of the answer, then tap the question to see it.
Which artery supplies the inner retina?
The central retinal artery, a branch of the ophthalmic artery.
Why does giant cell arteritis cause ischaemic optic neuropathy?
It occludes the posterior ciliary arteries, which supply the optic nerve head.
How can central vision survive a central retinal artery occlusion?
If a cilioretinal artery from the ciliary circulation supplies the macula.
Connections
See it in 3D5
The structures of Durgical's 3D anatomy where it is found.
Educational content; not a clinical guideline and no substitute for assessment by a health professional. For sudden visual loss, severe eye pain, a chemical burn or an eye injury, go to an emergency department at once.
Sources: Central Retinal Artery Occlusion (StatPearls Publishing (NCBI Bookshelf), 2024); Anatomy, Head and Neck: Eye Ophthalmic Vein (StatPearls Publishing (NCBI Bookshelf), 2023); Nonarteritic Anterior Ischemic Optic Neuropathy (StatPearls Publishing (NCBI Bookshelf), 2025).
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Representative model, for educational purposes only.