ophthalmology

1. BLOOD SUPPLY OF
THE EYE
PRESENTED BY:-
DR.SWARNA GAIKWAD
GUIDED BY:-
DR. MILIND CHANGOLE
10/02/2017

2. BLOOD VESSELS
Arteries
The arteries involved in the blood supply of ocular
structures and visual pathway include:
 Ophthalmic artery
 Cerebral arteries
 Circle of Willis
 External carotid artery

4. OPHTHALMIC ARTERY
Origin and relations
 Ophthalmic artery constitutes the main
source of blood supply for orbital
structures.
 It is a branch of Internal carotid artery.
 It arises from the medial side of the
convexity of the fifth bend of internal
carotid artery, just after it has left the
root of cavernous sinus after piercing the
dura .
 The ophthalmic artery , at its origin is
medial to the anterior clinoid process and
inferior to the optic nerve.

5. COURSE AND RELATIONS
After its origin the ophthalmic artery
passes through the optic canal within
the dural sheath of the optic nerve, lying
inferior to it.
At the apex of the orbit in the muscle
cone it pierces the dural sheath of the
optic nerve and comes to lie in lateral to
the optic nerve and medial to 3rd and 6th
nerve
At this point ciliary ganglion lies
between the ophthalmic artery and the
lateral rectus muscle.
Then the artery moves forward and
upwards and crosses over the optic
nerve and below the superior rectus
muscle and comes to lie over the medial
side of the optic nerve.

6. BRANCHES OF THE OPHTHALMIC ARTERY
 Central retinal artery
 Lacrimal artery - lateral palpebral
artery
 Recurrent meningeal artery
 Long and short postrior ciliary
arteries
 Muscular branches –anterior ciliary
arteries
 Supraorbital artery
 Medial palpebral artery
 Posterior ethmoidal artery
 Anterior ethmoidal artery
 Dorsal nasal artery
 Supratrochlear artery

7. CLINICAL SIGNIFICANCE
 Severe occlusion of the ophthalmic artery causes ocular
ischemic syndrome. As with central retinal artery occlusions,
ophthalmic artery occlusions may result from
systemic cardiovascular diseases.
 A cherry-red spot is typically absent and the vision is usually
worse.
Amaurosis fugax is a temporary loss of vision which cause a
temporary reduction in ophthalmic artery pressure.
Even complete occlusion of the ophthalmic artery may possibly
leave the eye without symptoms, probably because
of circulatory anastomoses.

8. CENTRAL RETINAL ARTERY
It arises from the ophthalmic artery near the optic
foramen and courses ahead with 5-6 right angle
bends as follows
 Outside the optic nerve
It runs a wavy course forward below the optic nerve 10-
15 mm behind the eyeball and pierces the dura and
arachnoid from which it recieves coverings.
 In the subarachnoid space
It runs a short course and invaginates the pia to reach
the centre of the optic nerve surrounded by a
sympathetic nerve plexus (nerve of Tiedemann).
 In the centre of the optic nerve
It bends forwards and then accompanies the vein which
lies temporally and pierces the lamina cribrosa.
 In the optic nerve head
It lies superficially in the nasal part of the physiological
cup covered only by a layer of glial tissue (connective
tissue meniscus of kuhnt ) which closes the cup.
It divides into 2 branches superior and inferior branch
which subdivides into nasal branch and temporal branch

9. CENTRAL RETINAL ARTERY
 In the retina
The 4 terminal branches of central
retinal artery namely the
 Superior nasal
 Superior temporal
 Inferior nasal and
 Inferior temporal
These branches divide
dichomtomously as they proceed
towards the ora serrata where they end
without anastomosis

10. ARRANGEMENT OF THE
RETINAL CAPILLARIESIn most of the extramacular fundus there are 2 retinal capillary
networks:-
1. Superficial
2. Deep
The superficial capillary network lies at the level of the nerve fibre
layer.
The deep one lies between the inner nuclear layer and the outer
plexiform layer.
Peripherally as the ora serrata is approached the capillary network is
reduced to a scanty single layer.
In the parafoveal zone the capillary network is especially well
developed and is three layered.
However there exists a capillary free zone in the fovea, known as the
foveal avascular zone(FAZ) .

12. BLOOD RETINAL BARRIER
•The endothelial cells of a normal retinal capillary are closely bound together about
the lumen by intercellular junctions.
•These junctions normally prohibit a free flow of fluids and solutes from the
vascular lumen into the retinal interstitium and thus form a barrier.
•The endothelial cells of the retinal capillaries are encircled by a basement
membrane around which is present a layer of pericytes.
•Pericytes are also surrounded by a layer of basement membrane.
•Normally the endothelial cells and the pericytes are present in 1:1 ratio in young
adults.
•But they decrease in advancing age and diabetes mellitus leading to leakage.

14. LACRIMAL ARTERY
•It arises from the ophthalmic artery when the latter
lies lateral to the optic nerve.
•It lies along the upper border of the lateral rectus
muscle in company with the lacrimal nerve to supply
the lacrimal gland.
LATERAL PALPEBRAL ARTERY
•It is a branch of the lacrimal artery and forms the
inferior and superior palpebral arcades by
anastomosing with the medial palpebral arteries and
supplies the lid and the conjunctiva.

15. RECURRENT MENINGEAL
ARTERY
After arising from the
ophthalmic artery in the
posterior part of the orbit and
passes backwards from the
superior orbital fissure.
It anastomoses with the
middle meningeal artery which
is the branch of the external
carotid artery forming an
anastomosis between the
internal and external carotid
arteries.

16. LONG AND SHORT
POSTERIOR CILIARY ARTERY
Two long posterior ciliary artery arise from the ophthalmic artery
below the optic nerve.
After giving 10-20 branches(the short ciliary arteries) the long ciliary
arteries move forward and pierce the sclera on the lateral and medial
side of the optic nerve.
Inside the eyeball, they move forward between the sclera and the
choroid to supply the ciliary body and then anastomose with the
anterior ciliary arteries to form the circulus arteriosus iridis major.
The short ciliary arteries pierce the sclera and enter the choroid to
form vasculature.
Circle of zinn is formed by a circular anastomosis between the short
ciliary arteries and lies close to the optic nerve and supplies the
choroid .

19. MUSCULAR BRANCHES OF
THE OPHTHALMIC ARTERY
Two main branches the lateral and the medial
1. The lateral supplies the
 lateral and superior rectus
 levator palpebrae superioris
 superior oblique muscle
2. The medial supplies the
 medial rectus
 inferior rectus and oblique

20. ANTERIOR CILIARY ARTERY
These are the branches of the
muscular branches.
Usually they are seven in number 2
from each superior , medial and
inferior rectus and 1 from lateral
rectus.
They pierce the sclera 4mm from
limbus and enter the eyeball to
anastomose with the long posterior
ciliary artery.

22. SUPRAORBITAL ARTERY
It springs from the ophthalmic artey as that vessel
is crossing over to the medial side of the optic
nerve.
It passes upward on the medial borders of the
superior rectus muscle and levator palpebrae
superioris , meeting the supraorbital nerve
accompanies it between the roof of the orbit
and levator palpebrae superioris to
the supraorbital notch.
When passing through the supraorbital notch it
divides into a superficial and a deep branch. Its
terminal branches anastomose with branches of
the supratrochlear artery and the superficial
temporal arteries.
This artery supplies the levator palpebrae

23. MEDIAL PALPEBRAL
ARTERIESThe medial palpebral arteries (internal palpebral arteries) are arteries of
the head. They are two in number, superior and inferior
They leave the orbit to encircle the eyelids near their free margins,
forming a superior and an inferior arch, which lie between
the Orbicularis oculi and the tarsi.
The superior palpebral arch anastomoses, at the lateral angle of the
orbit, with the zygomatico-orbital branch of the temporal artery and
with the upper of the two lateral palpebral branches from the lacrimal
artery.
The inferior palpebral arch anastomoses, at the lateral angle of the
orbit, with the lower of the two lateral palpebral branches from the
lacrimal and with the transverse facial artery, and, at the medial part of
the lid, with a branch from the angular artery.

24. POSTERIOR AND ANTERIOR
ETHMOIDAL ARTERIESPosterior is a small artery entering the
posterior ethmoidal canal along with the
posterior ethmoidal nerve and supplies the
mucous membrane of posterior ethmoidal
air sinus and superior part of nasal mucosa.
Anterior art arises from the ophthalmic
artery when lies between the superior
oblique muscle and the medial rectus
muscle along with the anterior ethmoidal
nerve.
It supplies the dura of ant. cranial fossa
nasal cavity and anterior ethmoidal air
sinus.

25. DORSAL NASAL ARTERY
It is the terminal branch of the ophthalmic artery and supplies the lacrimal
sac skin of root of the nose and anastomoses with facial artery.
Supratrochlear Artery
It is also one of the terminal branches of ophthalmic artery.
It supplies the skin muscles and periosteum of medial part of the forehead.

26. EPISCLERAL AND
CONJUNCTIVAL ARTERIESThese are small vessels derived from larger
branches of the ophthalmic artery and
supply the epislera and conjunctiva.
Blood to the bulbar conjunctiva is primarily
derived from the ophthalmic artery.
 The blood supply to the palperbral
conjunctiva (the eyelid) is derived from
the external carotid artery.
 However, the circulation of the bulbar
conjunctiva and palpebral conjunctiva are
linked, so both bulbar conjunctival and
palpebral conjunctival vessels will be
supplied by both the ophthalmic artery and
the external carotid artery.

27. CLINICAL SIGNIFICANCE
Disorders of the conjunctiva and cornea are a common source of eye complaints, in particular
because the surface of the eye is exposed to various external influences and is especially
susceptible to trauma, infections, chemical irritation, allergic reactions and dryness.
Type II diabetes is associated with conjunctival hypoxia increased average blood vessel diameter,
and capillary loss.
Sickle-cell anemiais associated with blood vessel sludging, altered blood flow and blood vessel
diameter, and capillary micro-haemorrhages
Hypertension is associated with an increase in the tortuosity of bulbar conjunctival blood vessels
and capillary and arteriole loss.
Carotid artery occlusion is associated with slower conjunctival blood flow and apparent capillary
loss.
With age, the conjunctiva can stretch and loosen from the underlying sclera, leading to the
formation of conjunctival folds, a condition known as conjunctivochalasis
The conjunctiva can be affected by tumorswhich can be benign, pre-malignant or malignant.
Leptospirosis an infection with Leptospira, can cause conjunctival suffusion,which is
characterized by chemosis, and redness without exudates.

28. ARTERIES OF THE BRAIN

29. INTERNAL CAROTID ARTERY
It enters the middle cranial fossa by passing through the carotid
canal and traversing the foramen lacerum.
It runs in the cavernous sinus and emerges in the anterior part of the
roof.
It lies lateral to the optic chiasma and terminates by dividing into
anterior cerebral and middle cerebral arteries.
Branches:-
1. Ophthalmic artery
2. Posterior communicating artery
3. Choroidal artery
4. Anterior cerebral artery
5. Middle cerebral artery

30. VERTEBRAL ARTERY
The two vertebral arteries enter the posterior cranial fossa by passing
through the foramen magnum.
They ascend upward forward and medially on the medulla oblongata
and unite with each other at the lower border of the pons to form the
basilar artery.
Branches of the cranial part of the vertebral arteries include
meningeal branches, posterior and anterior spinal branches, posterior
inferior cerebellar artery and medullary artery.
The basilar artery ascends in the groove on the anterior surface of
pons and at the upper border it divides into two posterior cerebral
arteries.

31. BASILAR ARTERY
The basilar artery ascends in the groove on the anterior surface of
pons and at the upper border it divides into two posterior cerebral
arteries.
Branches include pontine arteries ,labyrinthine artery, ant inf
cerebellar artery, sup Cerebellar artery.
Each post. Cerebral artery winds around the cerebral peduncle to
reach the cerebrum and supplies the cortex and are connected to the
internal carotid arteries through the posterior communicating arteries.
As fas as the vision is considered, the posterior cerebral arteries
supply almost whole of the visual cortex, posterior regions of the
optic radiations.
Posterior choroidal arteries( branches of the posterior cerebral
artery)arise near the lateral geniculate body and supply its
posteromedial aspect.

32. CIRCLE OF WILLIS
It lies in the interpeduncular fossa at the base of the brain
It is formed by
1. Ant. communicating artery
2. Ant cerebral arteries
3. Internal carotid arteries
4. Post. Communicating artery
5. Post cerebral artery
6. Basilar artery

33. It is thus a free anastomosis between the
2 internal carotid art and vertebral art.
This equalizes the pressure on both side
and allows blood that enters by either
internal or vertebral artery to supply blood
to any pat of both the cerebral
hemispheres.
Cortical and central branches arise from
the circle and supply the brain substance.

34. CLINICAL SIGNIFICANCE
Subarachnoid hemorrhage (SAH) is bleeding into the subarachnoid space — the area
between the arachnoid membrane and the pia mater surrounding the brain.
 SAH may occur spontaneously, usually from a ruptured cerebral artery, or may result
from head injury.
Subclavian steal syndrome
In subclavian steal syndrome, blood is "stolen" from the circle of Willis to preserve blood
flow to the upper limb.
 Subclavian steal syndrome results from a proximal stenosis(narrowing) of the subclavian
artery , an artery supplied by the aorta which is also the same blood vessel that eventually
feeds the circle of Willis via the vertebral artery.

35. EXTERNAL CAROTID ARTERY
It passes upwards through the neck and only
few branches supply the globe are
FACIAL ARTERY
Its branch the angular art supplies the
lacrimal sac, medial part of the lower lid and skin
and skin of the cheek and anastomoses with
infraorbital and dorsonasal artery
SUPERFICIAL TEMPORAL ARTERY
It is the terminal branch of the external carotid
carotid art that supply near the orbit are the ant
ant temporal ,the zygomatic and the transverse
transverse facial arteries
MAXILLARY ARTERY
It supplies the lower lid and lacrimal sac nd
anastomoses with angular and dorsonasal artery

36. VENOUS DRAINAGE
Venous drainage of structures of eye balls, lacrimal apparatus,
conjunctvita, eyelids and other structures has been described along
with the indidual structure.
In addition to the veins draining these structures, orbit also contains
inferior and superior venous networks.
The inferior venous network lies near the orbital floor.
The superior venous network is smaller and lies above the levator
palpebrae superioris muscles.
The main venous channels which ultimately get tributaries from
various orbital structures includes:
Superior ophthalmic vein
Inferior Ophthalmic vein
Middle Ophthalmic vein
Medial Ophthalmic vein
Angular vein

38. SUPERIOR OPHTHALMIC
VEIN
Superior ophthalmic vein start by joining of its superior and inferior
roots in the superomedial part of the anterior orbit, a few mm behind
the superior tendon.
the superior root of the superior ophthalmic vein starts after receiving
a communication from the angular vein and enters the orbit above the
medial palpebral ligament.
The inferior root of the superior ophthalmic vein begins after receiving
a communication from the angular vein . In the orbit, superior
ophthalmic vein accompanies the ophthalmic artery. It lies above the
optic nerve.
 It recieves tributaries corresponding to the branches of the arteries.

39. INFERIOR OPHTHALMIC VEIN
It commences from the inferior venous network near the anterior part of the
floor of the orbit.
It receives tributaries from the lower eyelid, lower and lateral ocular muscles,
conjunctiva, lacrimal sac, and the lower two vorticose veins.
It communicates with the
1. Pterygoid plexus of veins.
2. Anterior facial vein
3. Superior ophthalmic veins

40. MIDDLE OPHTHALMIC VEIN
It drains the inferior venous network and leaving the muscle cone
joins the confluence of the superior opthalmic vein in the cavernous
sinus.
Some workers have described it as second inferior ophthalmic vein. It
is seen in about 20% individuals.
Medial ophthalmic vein
It is present in about 40% individuals.
 It arises either from the inferior root or from the anterior part of the
superior ophthalmic vein. It runs backward along the medial most part
of the orbital roof and ultimately drains in to the cavernous sinus.

41. ANGULAR VEIN.
 It is formed by the union of the supratrochlear and
In the upper part a communication connects it with superior
ophthalmic vein.
 It runs down at side of the nose across the medial edge of the
palpebral ligament about 8mm from the medial canthus.
It lies lateral to the angular arteries. It is an important landmark
lacrimal sac surgery and when cut inadvertantly it bleeds
Below, the angular vein continues as the facial vein
. Tributaries: supraorbital vein, supratrochlear vein, superior
inferior superficial palpebral veins nasal branches

42. CAVERNOUS SINUS
It is a large venous space situated in the middle
cranial fossa , one each on either side of the body of
the sphenoid.
Its interior is is dived into trabeculae which are more
conspicuous in living then dead.
The floor of the sinus is formed by the endosteal dura
mater.
The lateral wall roof and medial wall is formed by the
meningeal dura mater anteriorly sinus extend upto the
medial end of sup orbital fissure and post upto the
apex of petrous temporal bone.
It is about 2 cm long and 1cm wide.

43. RELATIONS
Structures outside the sinus
Superiorly the optic tract internal carotid artery and
perforating substance.
Inferiorly foramen lacerum and the junction of the
the greater wing of sphenoid bone.
Medially hypophysis cerebri and sphenoidal air sinus.
Laterally temporal lobe with uncus.
Anteriorly sup orbital fissure.
Posteriorly apex of petrous temporal and crus cerebri
midbrain.

44. STRUCTURES PASSING
THROUGH CENTER
A) Internal carotid artery with venous and
sympathetic plexus around
B) Abducent nerve

45. STRUCTURES IN THE
LATERAL WALL
A)Occulomotor nerve
B)Trochlear nerve
c)Ophthalmic nerve
D)Maxillary nerve
E)Trigeminal ganglion

46. TRIBUTARIES (INCOMING
CHANNEL)A) From the orbit
•The sup ophthalmic vein
•A branch of the inferior ophthalmic vein
•Central vein of retina may drain into sup ophthalmic vein or into the
cavernous sinus
Medial ophthalmic vein
B) From the brain
•Superficial middle cerebral vein and inferior cerebral veins from the
temporal lobe.
C)From the meninges
•Sphenoparietal sinus
•The frontal trunk of the middle meningeal vein may drain either into

47. DRAINING CHANNELS
The cavernous sins drains into
the transverse sinus through the sup petrosal sinus.
Into the internal jugular vein through the petrosal
sinus and through a plexus around the internal carotid
artery.
Into the pterygoid plexus of veins passing through
the foramen ovale the foramen lacerum.
The right and left cavernous sinuses communicate
with each other through ant and post intercavernous
sinuses.

48. COMMUNICATIONS AND
SOURCE OF INFECTIONAll the communications are valveless and blood can flow
though them in either direction.
Ant and sup and inf. ophthalmic veins drain in the sinus and
these veins receive blood from face nose and paranasal sinuses
and orbits.
Therefore infection may spread from facial wounds furuncles
erysipelas orbital cellulitis and sinusitis.
Posteriorly the sup and inf. petrosal sinus leave to join the
transverse sinus and internal jugular veins respectively
Labyrinthine veins opening into the inferior petrosal sinuses
bring infections from the middle ear
Mastoid emissary veins may spread infection from the mastoid

49. Superiorly the cavernous sinus communicates wih the vein
of the cerebrum and may be infected from meningitis and
cerebral abscesess.
Inferiorly the sinus communicates with pterygoid plexus also
drains the tonsillar region.
Medially the cavernous sinus are connected with each other
by inter cavernous sinuses which account for transfer
infection.

50. ANATOMICAL PECULIARITIES OF
THE CEREBRAL ARTERIESCentral branches of cerebral arteries are end art thrombosis or rupture of
any of them invariably causes infarction the cortical branches establish very
poor anastomosis with each other and cannot compensate for any loss of
blood supply to a particular area of cortex.
There exists a blood brain barrier formed by the structures between the
blood and the nerve cells of the brain.
This barrier at the level of vessels is formed by:-
The vessel wall the arachnoid layer of perivascular sheath
The pial layer of perivascular sheath
neuroglia and the ground substance of the brain
The bbb allows selective passage of substances.
A free anastomosis in the form of circle of willis equalizes pressure in the
cerebral arteries.

51. CONTROL OF OCULAR
CIRCULATION
Like other tissues in the body , blood flow through the ocular tissues is also
regulated by local as well as systemic regulatory mechanisms
The main factors are:-
Pressure head(perfusion pressure)
Autoregulation and
Resistance to blood vessels and
Viscosity of blood.
Main site of vascular resistance is arterioles.
Precapillary sphincters which cause opening and closing of the capillaries in most
tissues of the body are conspicuously absent in choroid and retina, as a result blood
flow is steady
. The role of factors controlling occular blood flow are, perfusion pressure

52. CHEMICAL CONTROL OF
OCCULAR BLOOD FLOWHypercarbia causes vasodilatation of tissue and increases
blood volume.
 100% oxygen is associated with vasoconstriction.
In immature eye when exposed to high concentration there
occurs marked vasoconstriction and obliteration of vessels,
causing retinopathy of prematurity.
In relation of 7% Co2 and 21% o2 is reported to cause
moderate dilatation of blood vessels.

53. NERVOUS CONTROL
1 role of sympathetic supply
 Plays role in autoregulation
Maintains contant blood flow
2 role of parasympathetic supply
 Its role is much less clear
Causes vasodilatation in the whole uvea

54. THANK YOU!