1. The eye receives its blood supply from branches of the ophthalmic artery, which branches directly from the internal carotid artery. 2. The central retinal artery supplies the retina, while the ciliary arteries supply the choroid, iris, and ciliary body. 3. Veins drain blood from the eye and empty into the superior and inferior ophthalmic veins, which drain into the cavernous sinus. The cavernous sinus contains several cranial nerves.

1. Blood supply of
the eye
Dr. Amer A. Shamsulddin

2. Arterial blood supply:
• Internal carotid artery:
• External carotid artery:
Note:
(eyelids and conjunctiva from both internal and external carotid
arteries)

3. Internal carotid artery:
• First intracranial branch of the internal carotid just
as the artery exits from the cavernous sinus
• optic foramen below and lateral to the optic nerve
• Pass over the optic nerve to its medial side
• Between the MR and SO
• Terminates by dividing into dorsonasal and
supratrochlear
Ophthalmic artery:

4. Branches of ophthalmic artery:
• Central retinal a.
• Supra-orbital artery
• Posterior ciliary artery
– Long posterior ciliary a. (2 arteries)
– Short post. Ciliary a. (10-20 arteries)
• Muscular arteries
– Anterior ciliary a. (7 arteries)
• Lacrimal artery (terminate into zygomatic branches)
• Ant. And post. Ethmoidal arteries
• Superior and inferior palpebral arteries
• Dorsonasal artery
• Supratrochlear artery

6. Central retinal artery
• pierces the dural sheath of the optic
n. 12 mm behind the globe
• It gives off small meningeal branches
to supply the pial sheath of the optic
nerve.
• It’s functionally as end artery.

7. 1. ophthalmic artery.
2. central retinal artery
3. ciliary arteries (on each side of the
optic nerve). These vessels divide
into 2 long posterior ciliary
arteries(#4 in Figure) and ~20 short
posterior ciliary arteries (#5 in
Figure) that enter the eye
immediately adjacent and around the
optic nerve . The short posterior
ciliary arteries directly supply the
choroid and the long posterior ciliary
arteries travel in the suprachoroidal
space anteriorly (#6 in Figure) then
supply the choroid anteriorly via
recurrent branches.
posterior (#7 in Figure) and anterior (#8
in Figure) ethmoidal vessels.
The superior oblique muscle is shown for
orientation ( #9 in Figure).

8. Ciliary arteries
• Long post, short post. And ant. ciliary aa. are the major blood supply to the
globe
• Long post. Ciliary aa:
– Paired arteries that pierce the sclera outside the circle of Zinn snd
– travel forward in the suprachoroidal space to the ciliary body,
– Gives recurrent branches that supply the choroid anterior to the
equator and anastomose with short post ciliary aa.
• Short post. Ciliary aa:
– 10- 20 branches pierces the sclera around the optic n
– This anastomotic circle of Zinn supplies the optic n. head (optic disc)
– Supplies the choroid to the equator
• Ant. Ciliary aa:
– 7 arteries 2 for each rectus m. exept LR m. only 1
– Supply the sclera and conjunctiva and the iris

11. External carotid artery:
• External maxillary artery (facial artery)
– Angular artery
• Superficial temporal artery
• Internal maxillary artery
– Middle meningeal artery

12. Blood supply of the
eyelids
• The main arterial blood
supply:
– Lat. Palpebral a. (from
lacrimal artery)
– med. Palpebral a. ( from
ophthalmic artery)
• These palpebral aa. (from
internal carotid a.)
anastamose with facial artery
(external carotid) and its
branch (zygomatico-temporal a.
and angular a.) at the lat.
aspect of the lid and form the
Marginal and peripheral
palpebral arcades

13. Venous drainage:
• Medially: to
ophthalmic and
angular vv.
• Latrally: to
superficial
temporal v.

14. Lymph drainage
• Lat. 2/3 of upper
and lower lids
superficail parotid
nodes (pre-
auricular nn.)
• Medial 
submandibular
nodes

15. Nerve supply:
• Lower lid:
– infra-orbital (from V2)
– Med. Aspect  infra-
trochlear n. (V1)
• Upper lid:
– Supra-orbital n.
– Supra-trochlear n.
– Lacrimal n. (v1)

16. Blood supply to the conjunctiva
• Palpebral conjunctiva marginal and peripheral
arcades (from med. And lat. Palpebral aa.)
• Limbal conjunctiva  ant. ciliary art.
• Venous drainage:
The conj. veins  sup. and inf. ophthalmic vv.
• Nerve supply:
Bulbar conj.  long ciliary nn. (nasocialiary of ophth. n.)

17. Blood supply of the AC
Long post. ciliary aa. anastomose with ant. ciliary aa.
– Major arterial arcade (ciliary stroma)
– Minor arterial arcade (At the collarete of the iris)
• They are the major blood supply to the iris and ciliary body
• Iridial vessels are non-fenestrated (endothilial tight junctions)
• Vessels in the ciliary body are fenestrated and no tight junctions
• Blood-aqueous barrier  tight junctions in the ciliary epithelium
• Venous drainage: follow the aa.  minor venous circle directly
into the vortex veins (not into the corresponding major circle)

19. retinal blood supply:
• The outer plexiform layer is
the watershed region
• Outer to this layer
(neuroreceptors and RPE)
 choroidal circulation by
diffusion
• Inner 2/3  central retinal
a. directly
• Retinal aa. run in the nerve
fiber layer with 4 branches
for each quadrant

20. • Retinal capillaries are concentrated in the macula
but are absent from the fovea centralis (FAZ)
• In 20% of people there’s cilioretinal a. (from post.
ciliary a.) supplies the macula

21. Blood retinal barrier
• Inner BRB:
– Tight junctions between the endothelial cells or
retinal blood vessels
• Outer BRB:
– Tight junctions between
RPE cells

22. Blood supply to the visual pathway
• Intra-ocular optic n. short post. ciliary aa.
That form the circle of Zinn.
• The central retinal a. pierces the dural sheaths
of the orbital optic n. but doest supply it, it’s
supplied by pial plexus of vessels
• Intracraneal optic n. is supplied by the
superior hypophyseal and ophthalmic aa.
• A rise in the ICP may compromise blood flow to these vessels 
papilloedema

24. • Optic tracts pial arteries (from ant.
Choroidal and post. Communicating aa)
• Lat. Geniculate body and post. aspect of
optic radiations  the middle cerebral a. with
the post. Cerebral a.
• Visual cortex:
– Most of its blood supply post. Cerebral a.
– Occipital pole (macular area)Middle cerebral a.
(causing macular sparing in some of occipital lobe
strokes)

25. Venous drainage of
the eye

26. • There 4 vortex veins
(2 on each side)
exit the eyeball
post. to the equator.
• Sup. Vortex vv. and central retinal v. Superior
ophthalmic v. (which is from supra-orbital and facial vv.)
• Inferior vortex vv.  Inf. Ophthalmic v. which:
– may drain to the sup. Ophthalmic v or directly to
cavernous sinus
– communicates with the pterygoid venous plexus (and
because of the reason the inf. From this plexus may reach
cavernous sinus  cavernous sinus thrombosis)

28. Cavernous sinus
• Extends from the sup. orbital fissure ant.ly to
the apex of petrous bone (temporal bone)
• Floor  dural coverings of greater wing of
sphenoid
• Med body of sphenoid and pitiutary fossa

29. • Internal carotid a.
grooving the medial wall
of the sinus then pierces
its roof.
• The abducent nerve (VI)
travels within it
(first nerve to damage by cavernous
sinus thrombosis)
• Its lat. Wall encloses III,
IV, V1 & V2 nerves.