ophthalmology

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.