This document provides an overview of the anatomy of the uveal tract, which includes the iris, ciliary body, and choroid. It begins with an introduction and overview of the embryology and development of the uveal tract. It then discusses the anatomy and microstructure of each part of the uveal tract in detail, including their nerve and blood supply. It also briefly discusses some congenital anomalies that can affect the uveal tract.

1. UVEA: ANATOMY, NERVE &
VASCULAR SUPPLY

2. 1. Introduction
2. Embryology of the uveal tract
3. Congenital anomalies of uveal tract
4. Iris: anatomy and nerve supply
5. Ciliary body: anatomy and nerve supply
6. Choroid: anatomy
7. Blood supply of uveal tract
8. Clinical Correlation
Presentation layout

3. •Coined from latin word Uva- grape
•Middle vascular coat of eyeball
•From anterior to posterior:
- iris
- ciliary body
- choroid
INTRODUCTION

4. Uveal tract firmly attached to sclera only at 3
sites:
• the scleral spur
• the exit points of vortex veins
• the optic nerve

5. c
1)Epithelium-
Neuroectodermal
2)Sphincter &
Dilator pupillae-
Neuroectodermal
3)Stroma&blood
vessels-
Mesenchyme
Epithelium-
Neuroectodermal
Stroma,ciliary
muscles & blood
vessels -
Mesenchyme
Mainly derived from
inner vascular layer
of mesenchyme that
surrounds the optic
cup.
Melanocytes –
originate from
neural crest
Embryology

6. Milestones
9th week of gestation Ciliary body begins to appear
12th week of gestation Sphincter pupillae appears
4th month Ciliary processes fully formed
5th month Iris and choroid are formed
6th month Dilator muscles begin to form
Sphincter muscle fully differentiated
Postnatal period dilator muscles reach adult
proportion by 5 years

7. Towards the end of gestation , the
central iris stroma disappers forming
pupil.
At birth dilator pupillae is poorly
developed & pupil response poorly to
mydriatics.

8. Congenital anomalies of uveal tract
Aniridia (Iridremia)
-congenital absence of Iris
-true aniridia i.e complete absence of iris rare
-a peripheral rim of iris present & this is called
clinical Aniridia

9. Heterochromia of iris
Heterochromia iridium Heterochromia iridis
Color of one iris differs from
the other
One sector of iris differs
from the remainder of iris

10. Uveal coloboma
Typical coloboma:
Located inferonasally in the
region of closure of embryonic
fissure
a.Complete coloboma:
Extends from pupil to optic
nerve
Includes retina, choroid,
ciliary body, iris
b. Incomplete coloboma:
Involve the iris alone, or iris and
ciliary body, or iris, ciliary body
& part of choroid

11. Atypical coloboma
- Occasionally found in other positions i.e. not
related to fissure closure
- It is usually incomplete
Persistent pupillary membrane
- Represents the remnants of vascular sheath of
lens
- Strands arise from and insert into the iris
collarette.

12. IRIS
• Greek Word Iris - color haloes/rainbows
• Anterior most part of the uvea
• Diameter -12 mm
• Thickness -0.5 to 0.6 mm
• 3 to 4 mm aperture slightly nasally- pupil
• Attached to the middle of anterior surface of ciliary body
• Thinnest at root and tears easily- Iridodialysis

13. POINT TO BE NOTED
Pupillary margin rests
lightly on anterior
surface of lens so when
lens is removed the iris
is flat and often
tremendous

14. Macroscopic structure
Anterior surface
1. ciliary zone:
- radial steaks
- crypts: peripheral & central
- contraction furrows
2. pupillary zone:
- about 1.6mm wide, lies between collarette and
pigmented pupillary frill
Collarette:
represents the attachment of pupillary m/m
lies 2mm from the pupil margin
thickest region of iris

16. Posterior surface
- dark brown or black
- looks smooth
under magnification:
-schwalbe’s contraction folds:
radial furrows, commence 1mm from pupillary border
-schwalbe’s structural furrows:
start 1.5mm from pupillary border, narrow and deep to
start with but becomes wide and shallow as they approach the
ciliary margin
-circular furrows:
finer than radial furrows
cross the structural furrows at regular interval
more marked near the pupil

17. Contact between the posterior
surface of iris and anterior
capsule of the lens is also
altered by pupillary size
It is greatest on mid dilatation
Precipitate angle closure
glaucoma in some predisposed
eye with narrow angle

18. Microscopic structure
1. Anterior limiting layer
2. Iris stroma
3. Anterior epithelial layer
4. Posterior pigmented epithelial layer

19. 1.Anterior limiting membrane
•Condensed part of the stroma
•Consists of melanocytes and fibroblasts
•Deficient in areas of crypts, very thin at contraction
furrows
•Determines the color of iris
3 types of intercellular junctions present
- gap junctions
- intermediate junctions
- discontinuous tight junctions

20. 2. Stroma
• Main bulk of iris tissue
• Consists of loosely arranged collagenous network
with mucopolysaccharide ground substance
contains
-the sphincter pupillae muscles
- dilator pupillae muscles
-the vessels and nerves of iris
-cellular elements: fibroblast, melanocytes, clump
cells and mast cells

21. Sphincter pupillae muscles
- 0.7mm wide , 0.1-0.17mm thick
- Encircles pupillary margin
- lies in stroma deep to the surface
- -
Even after broad iridectomy , which removes a sector of
iris sphincter,the remaining sphincter can still constrict
the remaining pupil margin
Origin is from anterior epithelium,but actually
separated from this layer by a thin sheet of collagen
& dilator fibre processes, to which it is firmly bound.
-Innervated by parasympathetic via short ciliary nerve

22. Dilator pupillae muscle
- 60um long &7um wide
- Filled with myofilaments
- Extend from iris root towards pupil
- When the muscle contract,it pulls the pupillary
margin towards the ciliary body,
dilating the pupil
- Innervated by sympathetics via long ciliary nerve
At birth dilator is poorly developed &pupil response poorly
to mydriatics

23. Parasympathetic Control of pupillary Size
Sphincter Pupillae
Short ciliary Nerve
Ciliary Ganglion
Inferior Oblique
Muscle
Oculomoter Nerve
Edinger Westpal
Nucleus

24. Dilator muscle
Long ciliary nerve
Ciliary ganglion
Ophthalmic division of Vth nerve
Cervical ganglion
Ciliospinal centre of Budge
Posterior Hypothalamus
Sympathetic Control of Pupillary Size:

26. Blood vessels
- form bulk of iris stroma
- they arise mainly from circulus arteriosis major
- some also arise directly from anterior ciliary arteries
- responsible for radial streaks seen on anterior surface of
iris
Peculiarities of iris : Absence of internal elastic lamina
non fenestrated capillary endothelium

27. Cellular elements of stroma
1) Fibroblast
• most common stromal cell
• found around blood vessels, nerves, muscle
tissue and throughout the iris substance
2) Melanocytes
• branching elements with processes
• contain melanin granules

28. 3) Clump cells
• large round pigment cells without processes
• filled with inclusion granules
4) Mast cells
• They are round
• Have villous processes
Extracellular matrix of stroma
-Contain type VI collagen
-Laminin and fibronectin

29. 3. Anterior epithelial layer
• anterior continuation of pigment epithelium of
retina and ciliary body
• lacking in melanocytes
• basal processes of the cells of this layer give
rise to dilator pupillae muscle

30. 4. Posterior pigmented epithelial layer
• anterior continuation of non pigmented epithelium
of ciliary body which in turn is the continuation of
sensory retina
• this layer derived from the internal layer of optic
cup
• contain abundant columnar type pigment cells
• It curves around the pupillary margin and extends
for a short distance onto anterior border layer of
iris stroma as the pigment ruff.

31. - In Rubeosis iridis, this pigmented layer extends farther onto
the anterior surface of the iris, a condition called Ectropion
uveae
Clinical significance

32. Forward bowing of iris
Angle closure glaucoma
Contact betweet the posterior surface of
iris and lens creates a relative pupillary
block to the flow of aqueous humor
through the pupil,which is more marked
in mid dilatation

33. Applied anatomy
Iris nodules
- Accumulated deposits of epithelioid cells and lymphocytes
deposited onto the iris without tissue destruction.
Two types:
Koeppes nodule at pupillary border Busaccas nodules near collarette

34. Iris atrophy
- areas of degeneration of iris
- Commonly seen in iridocyclitis

36. • Forward continuation of the choroid at ora serrata.
• In cut section, triangular in shape
CILIARY BODY

37. • Anterior side of triangle- part of anterior chamber angle
• in middle- attached to the iris
• Outer side of triangle lies against the sclera with a
suprachoroidal space in between
• Inner side of triangle divided into 2 parts:
1) pars plicata - anterior
2) pars plana - posterior

38. 1) Pars plicata / corona ciliaris
• anterior part
• about 2 to 2.5 mm long
• contain ciliary muscles
• have finger like ciliary processes
2) Pars plana / orbicularis ciliaris
• posterior smooth part
• 5mm wide temporally
• 3 mm wide nasally
• Viterous base gain attachment to the
epithelium of pars plana

40. Microscopic structure
From without inwards, consists of five layers:
1) Supraciliary lamina
2) Stroma of the ciliary body
3) Layer of pigmented epithelium
4) Layer of non-pigmented epithelium
5) Internal limiting membrane

41. 1) Supraciliary lamina
• outermost condensed part of stroma
• consists of pigmented collagen fibres
• Posteriorly,continuation of suprachoroidal lamina
• Anteriorly, continues with the anterior limiting membrane of
iris
2) Stroma of the ciliary body
• consists of collagenous connective tissue and fibroblast
• embedded in it:
a. ciliary muscle
b. blood vessels
c. nerves

42. Ciliary muscle
• non striated, smooth muscle
• occupies most of the outer part of the ciliary body
three main groups:
1) the longitudinal or meridional fibres
2) the oblique or radial fibres
3) the circular fibres

43. 1) Longitudinal or meridional fibres
- most external and closest to the sclera
- pass posteriorly into the stroma of ciliary body
2) Oblique or radial fibres
- occupy the midportion of the ciliary body
- radiate out from the scleral spur
3) Circular fibres
- occupy anterior and inner portion of the ciliary body
- nearest to the lens
- runs parallel to the limbus
- directly act as sphincter

44. Main action of all parts of ciliary muscles is to
slacken the suspensory ligament of lens & thus
helps in accommodation.
-Longitudinal muscle fibres form tendinous attachment
to the scleral spur: contraction increases aqueous flow
by opening up the spaces of trabecular meshwork

45. Contraction of the ciliary muscle, especially longitudinal
and circular fibres pulls the ciliary body forward in
accommodation.

46. Vascular stroma
-contain major arterial circle just in front of circular
fibres of the muscle
- Arterial circle is formed by the anastomosis between
the long posterior ciliary arteries and anterior short
ciliary arteries and send branches to iris and ciliary
body

47. 3) Layer of pigmented epithelium
• forward continuation of RPE
• anteriorly, continuous with anterior epithelium of
iris
4) Layer of non-pigmented epithelium
• consists mainly of low columnar or cuboidal cells
• forward continuation of sensory retina which stops
at ora serrata.
• continues anteriorly with posterior pigmented
epithelium of the iris

48. 5) Internal limiting membrane
• lines the non-pigmented epithelium
• forward continuation of internal limiting membrane of
the retina.

49. Nerve supply of the ciliary body
• these run from the nasociliary branch of the ophthalmic
division of the trigeminal nerve, running in the long ciliary
nerve
• these fibres enter the ciliary body and terminate in iris,
cornea and ciliary muscle.
Sensory fibres:

50. Sympathetic fibres:
Cervical
sympathetic
trunk
Synapse in
superior cervical
ganglion
Long ciliary
nerve
Ciliary muscles
Edinger
Westpal
nucleus
Oculomoter
nerve
Ciliary
ganglion
Short
ciliary
nerve
Ciliary
muscle
Parasympathetic fibres

51. Ciliary processes
• Whitish finger-like projections from
pars plicata part of the ciliary body
• 70 to 80 in number
• Each process is about 2mm long and
0.5mm in diameter
• Form the site of aqueous production

52. Ultrastructure of ciliary processes
Consists of:
a. The network of capillaries
b. Stroma of ciliary processes
c. Two layers of epithelium

53. a. The network of capillaries
• occupies the centre of each process
• each capillary consists of a very thin endothelium with
fenestration
• lined by basement m/m
• mural cells or pericytes present within basement
membrane

54. b) Stroma of the ciliary process
• very thin
• separates capillary network from epithelial layers
• consists of ground substance: mucopolysaccharide,
proteins & solute of plasma
• few collagen connective tissue fibres
• wandering macrophages

55. c) Two layers of epithelium
• their apical surfaces in apposition to each other
outer pigmented epithelium:
• contains numerous melanin granules
inner non-pigmented epithelium:
• contain mitochondria, zonula occludentes & lateral
and surface interdigitations.
• the tight junction between cells of this layer form
blood aqueous barrier

57. • Posterior portion of the middle vascular coat
• Extremely vascular
• Extends from optic disc to ora serrata
• The inner surface: smooth, brown and lies in contact with RPE
• The outer surface: rough and attached to sclera
• Posteriorly-0.22 mm thick
• anteriorly-0.1 mm
CHOROID

58. • Firmly attached to the margin of the optic disc
• Loosely at points where vessels and nerves enter it
• Attachment to sclera is strongest behind the sclera

59. Microscopic structure
From without inwards, consists of four
layers:
1) Suprachoroidal lamina (lamina fusca)
2) Stroma of the choroid
3) Choriocapillaries
4) bruch’s membrane (basal lamina or
lamina vitrae)

60. 1) Suprachoroidal lamina
• thin membrane 10 to 34 μm
• made of condensed collagen fibres, melanocytes and
fibroblasts
• continues anteriorly with supraciliary lamina
• space between this m/m and sclera: suprachoroidal
space (contain long & short posterior ciliary arteries and
nerves)

61. -contains vessels, nerves, cells & connective tissue
-stromal cells include:
a. melanocytes
b. fibrocytes
c. macrophages
d. mast cells
e. plasma cells
2) Stroma of the choroid
Main bulk is formed by vessels, arranged in two layers:
a. Haller’s layer: outer layer of large vessels
b. Sattler’s layer: inner layer of medium vessels

62. • consists of a rich bed of wide bore fenestrated capillaries
(18 to 50μm)
• receives most of its blood from medium & large vessels
of stroma
• nourishes RPE & outer layers of sensory retina
• density greatest at macula
3) Choriocapillaries
• choriocapillaries are divided into non
overlapping lobules or hexagonal
patches

63. • innermost layer of choroid
• thin non cellular lamina
• lies between choriocapillaries and pigment epithelium
of the retina
• 2 to 4 μm thickness
4) Bruch’s membrane

64. Comprises of five layers
a. Basal lamina of RPE
b. Inner collagen layer
c. Middle elastic layer
d. Outer collagen layer
e. Basal lamina of choriocapillaries

65. • Choroidal ischaemia often occurs as a pale hexagonal patches
(mosaic pattern)
• during choroidal phase of FFA, these lobules fill
independently from one another, giving a transiently patched
or blotched appearance
Clinical significance

66. Bruchs membrane become thickened with
increasing age and produces hyaline
excrescence known as drusens

67. Uveal tract supplied by 3 sets of arteries:
1) Short posterior ciliary arteries
2) Long posterior ciliary arteries
3) Anterior ciliary arteries
BLOOD SUPPLY OF THE
UVEAL TRACT

68. 1) Short posterior ciliary arteries
Arise as two trunks from the ophthalmic
artery
Each trunk divides into 10 t0 20 branches
Pierce the sclera around the optic nerve
Supply the choroid in segmental manner

70. 2) Long posterior ciliary arteries
Arise as nasal and temporal branch from
the ophthalmic artery
Pierce the sclera obliquely on medial &
lateral side of optic nerve
Run forward in suprachoroidal space to reach
ciliary muscle without giving any branch
Anastomose with each other & with the
anterior ciliary arteries to form major
arterial circle
Also give branches which supply the
ciliary body

71. 3) Anterior ciliary arteries
Derived from muscular branch of
ophthalmic artery
7 in number: 2 each from arteries of SR,
IR & MR, 1 from that of LR
These pass anteriorly in episclera
Give branches to sclera, limbus &
conjunctiva
Ultimately pierce the sclera near the
limbus to enter ciliary muscle

72. Anastomose with two long posterior
ciliary arteries to form major arterial
circle
Branches arise from major arterial
circle to supply ciliary process (one
branch for each process)
Many branches from major arterial
circle run radially through iris towards
pupillary margin
Anastomose with each other to form
minor arterial circle

74. • four in number (superior temporal, inferior temporal,
superior nasal and inferior nasal)
• pierce sclera obliquely on each side of SR and IR
muscles about 6 mm behind the equator
-drain blood from:
• whole of choroid
• receive small veins from ONH
• small veins from retina
• from iris, ciliary process, ciliary muscle, anterior part of
choroid
3) Venae vorticosae
(vortex veins or posterior ciliary veins)

75. • two superior vortex veins open into superior ophthalmic vein
• two inferior vortex veins open into inferior ophthalmic vein

76. Uveitis:
Inflammation of uveal tissue only
Classification:
1.Anterior uveitis:
Some clinically applied aspects
Inflammation of uveal tissue from iris upto pars
plicata of ciliary body
-Iritis: inflammation predominantly affect iris
-Iridocyclitis: iris and pars plica part of ciliary
body are involved
-Anterior cyclitis: pars plicata part of ciliary body
is predominantly affected

77. 2.Intemediate uveitis:
Inflammation of pars plana and
peripheral part of retina and underlying
choroid
3.Posterior uveitis:
Inflammation of choroid and retina
Hence the term choroiditis, chorioretinitis,
retinochoroiditis or neurouveitis is used
4.Panuveitis:
Inflammation of whole uvea

78. Pain
Redness
Photophobia
Salient features of uveitis

79. Posterior
synechiae
Cataract Glaucoma
due to PAS
Band
keratopathy
Complications of uveitis

80. Aqueous cells:
-presence of inflammatory cells in the anterior chamber
-the inflammatory response causes white blood cells such as
neutrophils, monocytes and lymphocytes to leave the
inflamed iris vessels to reach aqueous humour.
Grading
+1: 1-5cells
+2: 6-15cells
+3: 26-50cells
+4: over 50

81. Aqueous flare
- Turbidity of the aqueous humour caused by increased
protein level
- Blood aqueous barrier breakdown results in protein
(albumin) exudation in the anterior chamber giving the
normally clear, colorless aqueous humour a milky
appearance k/a flare
Grading
+1:faint(just detectable)
+2:moderate flare with
clear iris and lens
+3: marked flare(iris
and lens details hazy)
+4: intense flare(Fibrin
or plastic aqueous