1.
D R . P R A T E E K V I S H W A K A R M A
D N B O P H T H A L M O L O G Y
BLOOD SUPPLY OF VISUAL
PATHWAY

2.
Introduction
 Arteries of Brain :
Circle of willis
Circle of willis :
 Lies in interpeduncular fossa
at the base of brain.
 Encircles the pituitary stalk
 provides important
communications between the
blood supply of the forebrain
and hindbrain

3.
 Formed by:
Anterior communicating art
Ant cerebral art
Post communicating art
Post cerebral art
Basilar art
 Basically a free anastomosis
bertween 2 ICA and 2 VA

4.
Vertebral Artery
 Enter post cranial fossa
through foramen magnum
 Ascends upward, forward
and medially on
medulla oblongata
 unite at lower border
of pons to form
BASILAR Artery.

5.
 Br. Of Cranial part of Vertebral artery:
1. Meningeal br
2. Post spinal art
3. Ant Spinal art
4. Post inferior cerebellar
art
5. Medullary art

6.
Basilar Artery
 Ascends in groove on anterior surface of pons and at
upper border divides into two PCA.
 Br. Of Basilar art:
1. Ant Inf cerebellar art
2. Sup cerebellar art
3. Labyrinthine art
4. Pontine art
5. Posterior Cerebral Art:

7.
Posterior Cerebral Art
1.visual cortex
2.posteromedial aspect of LGB
3.post region of optic radiation
Calcarine artery: whole of
Visual cortex and posterior
portion of Optic Radiations
Posterior choroidal artery:
post medial aspect of LGB
Posterior choroidal artery

8.
Internal carotid artery
1. Cervical
2. Petrous,
3. Cavernous and
4. Cerebral part

9.
Internal carotid artery
 Enters middle cranial fossa through carotid canal
 Passes through foramen lacerum
 Runs in cavernous sinus
 Emerge from anterior part of its
roof
 Lies lateral to OC

10.
Cerebral Part:
(Mn: CAMP Off)
 Ophthalmic art
 Choridal art:
chaisma,
optic tract (post aspect),
LGB (ant and lateral aspect) and
commencement of optic radiations.

11.
 Ant Cerebral:
upper aspect of chiasma,
intra cranial part of optic nerve.
 Middle Cerebral: largest branch
superolateral aspect of cerebrum,
inferolateral aspect of chiasma,
optic radiation,
small part of visual cortex
 Post Communicating Art: joins Post Cerebral art to form
part of C.O.W.

12.
Ophthalmic Artery
 Br of ICA (after it leaves the roof of cavernous sinus)
 At origin: inf to ON
 Pass through the Optic
canal within dural sheath
of ON

13.
 At the apex of Orbit: lateral to ON and medial to occulomotor and
abducent nerve and

14.
 Runs forward and upwards
over Optic nerve ,below
Superior rectus and then comes
to lie medial to ON
 Ends by dividing into:
dorsal nasal art
supra trochleaar art
 The ophthalmic artery and its
branches are tortuous to
accommodate for the
movements of the eyeball.

15.
 Branches of Ophthalmic Artery:
1. Central retinal art
2. Long and Short posterior Ciliary art
3. Muscular art: Ant ciliary art
4. Lacrimal art: Lateral palpebral art
5. Medial palpebral art
6. Supra orbital art
7. Anterior ethmoidal art
8. Posterior ethmoidal art
9. Recurrent meningeal art
10. Dorsal nasal art (terminal br.)
11. Supra trochlear art(terminal br.)

16.
Long and Short Posterior Ciliary Artery
 Two long post ciliary art : arise from ophthalmic art below ON
 10-20 Short ciliary arteries: forms part of choroidal circulation

17.
BLOOD SUPPLY OF VISUAL PATHWAY

18.
Blood Supply Of Retina
 Outer four layers: Choriocapillaris
 Inner six layers: Central retinal artery
 Outer plexiform layer: Watershed area
It gets blood supply from both,
the central retinal artery
and choriocapillaris.

19.
Central Retinal Artery

20.
 In the optic nerve head:
Superficial in the nasal part of
the cup
Covered by a thin layer of glial tissue
(meniscus of Kuhnt, which separates
the vessels from the vitreous)
Divides into superior and
inferior branches
at disc margin: sup and inf br. Divide into nasal and temporal br.

21.
 In the retina: The four terminal branches divide
dichotomously and end without anastomosis

22.
 One of the capillary plexuses is
in the superficial zone
(nerve fibre layer)and the other
one is at the junction of
inner nuclear and outer plexiform
layer.

23.
Macula
 Superior and inferior temporal branches of central retinal
artery
 Cilioretinal artery:
It is seen in some individuals.
It is a branch of ciliary system of vessels.
 Supplies macula
It helps to retain the central vision
in the event of CRAO.
Fovea: Avascular area (500 µm)
Mainly supplied by choriocapillaris

24.
CRAO
 Nearly always at the lamina cribrosa
 Generally, due to an embolus, there may be
associated arteriosclerosis, hypertension or
Buerger disease
 Sudden and complete blindness, opaque and milky
white retina, cherry red reflex at the fovea

25.
Venous drainage of retina
 Central retinal vein and its branches follows same
pattern as CRA
 Empties into sup and inf ophthalmic veins
 Which drains into Cavernous sinus

26.
CRVO
 Presentation : sudden, u/l blurred vision.
 Fundus: tortuosity and dilatation of all branches
with Dot/blot and flame shaped
hemorrhages in all 4 quad most
numerous at periphery
cotton wool spots ,
macular edema

27.
Blood Supply Of The Optic Nerve
 Differ significantly depending upon which segment is
considered
 Intraocular
 Intraorbital
 Intracanalicular
 Intracranial

28.
Intraocular (ONH)
 Venous drainage of ONH- central retinal venous
system

29.
AION
 Defect in the blood supply of anterior part of the
optic nerve by posterior ciliary artery - AION
 It produces a postlaminar infarct.
 Can be inflammatory (arteritic) or Non-
inflammatory (non arteritic)

30.
Intraorbital
 Intraorbital optic nerve is 3cm
long while the entry of the
central retinal artery is
5-15.5mm behind the globe.
 So, the optic nerve here, is
divided into two segments,
proximal and distal.
 Distal segment:
Axial supply, in addition
 Proximal segment:
Centripetal branches of pial network
formed from br. Of PCAs

31.
 Periaxial system of vessels:
1. Ophthalmic artery
2. Long posterior ciliary arteries
3. Short posterior ciliary arteries
4. Lacrimal artery
5. Central retinal artery
6. Circle of Zinn
 Axial system of vessels:
1. Intraneural branches of central retinal artery
2. Central collateral arteries from central retinal artery

32.
PION
 Disorders affecting small pial vessels supplying the
intraorbital part of the optic nerve
 Vision loss with afferent pupillary defect.
 No visible ophthalmoscopic abnormality
 It can occur in disorders with vasculitis and
conditions producing acute systemic hypotension.

33.
Intracanalicular
 Lies in a watershed zone
 Anteriorly from collateral br of Ophthalmic art
 Posteriorly from pial vessels from
-ICA and
-Superior hypophyseal arteries.
 As opposed to Intraorbital part of ON, which moves
freely as the eye moves, the intra canalicular part is
tightly fixed to optic canal, making it vulnerable to
shearing injury in # skull

34.
Intracranial
 Exclusively supplied by the periaxial system of
vessels
Pial plexus:
1. Direct branches of internal carotid artery OR
Recurrent branch of anterior superior hypophyseal artery:
They supply to the inferior aspect of the optic nerve.
2. Branches from anterior cerebral artery:
They supply to the superior aspect of the optic nerve
3. Recurrent branches from the ophthalmic artery
4. Twigs from the anterior communicating artery

35.
Venous drainage of optic nerve
 central retinal vein (primarily) and
 pial plexus of veins
 ophthalmic vein.
 The intracranial part is drained by anterior
cerebral and basal veins.

36.
Optic chiasma
 Mainly derieved from br of Ant cerebral and Internal
carotid art.
 Superiorly: Anterior cerebral and anterior communicating
arteries
 Inferiorly: Internal carotid artery, anterior superior
hypophyseal artery and posterior communicating artery
 A branch of the ophthalmic artery supplies the antero-
inferior margin of the chiasma.

37.
Venous drainage
 Superior chiasma › Anterior cerebral vein
Inferior aspect of chiasma › Basal vein

38.
Optic tract

39.
Optic tract
 Venous drainage: Anterior cerebral vein and basal
vein

40.
Lateral geniculate body
Post Choroidal art

41.
 Occlusion of Anterior choroidal artery produces
produces an upper- and lower-sector field defect.

42.
 Occlusion of Posterior choroidal art produces a
homonymous horizontal sectoranopia

43.
Optic radiations
Anterior
part of optic
radiations
Middle part
of optic
radiation
Perforati
ng br. Of
MCA
Posterior
part of optic
radiations
Venous
drainage:
Basal vein
and middle
cerebral
vein

44.
Visual cortex
 calcarine branches of PCA
 Anterior end of the calcarine sulcus: Middle cerebral artery
 At the occipital pole of the cortex, there is an anastomosis between
posterior and middle cerebral arteries. Therefore, in thrombosis of
posterior cerebral artery, macula is spared.
 Internal occipital vein › Great cerebral vein of Galen & straight sinus
 Inferior cerebral vein › Cavernous sinus