Anatomy and Applied aspects of Uvea By Dr Rasika and Dr Ankit

1. ANATOMY AND APPLIED
ASPECTS OF UVEA
Presented by: Dr Rasika Bagewadi
Dr Ankit Gupta
Moderator: Dr Kher Ma’am
Conductor: Dr Nagpure Ma’am

2. EMBRYOLOGY
• Choroid: inner vascular layer of mesenchyme that
surrounds optic cup
Melanocytes of choroid originate from neural crest.
• Ciliary body: both epithelial layers from anterior part
of two layers of optic cup
Stroma, ciliary muscle and blood vessels from vascular
layer of mesenchyme surrounding optic cup.
• Iris: both epithelial layers from marginal region of
optic cup
Sphincter and dilator pupillae: anterior epithelium of
neuroectoderm
Stroma and blood vessels: vascular layer of
mesenchyme present anterior to optic cup.

3. ANATOMY
• Uvea constitutes the
middle vascular part of
the eyeball.
• It can be divided three
parts from anterior to
posterior: iris, ciliary
body and choroid.

4. IRIS
• It is a thin circular disc which lies most anteriorly.
• Its average diameter is 12mm and thickness is
0.5mm.
• Pupil is the aperture which is present centrally. Its
diameter is 3-4mm. It regularises the amount of
light reaching the retina.
• Iris is the thinnest at its root and tears away easily
from the ciliary body, called as iridodialysis,
during blunt trauma.
• Iris divides the space between cornea and lens
into anterior and posterior chamber.

6. • Average diameter is 12mm
• Thickness is 0.5mm, thickest at collarette, which is located
approximately 2mm from the pupillary margin and thinnest
at iris root(thickness-0.5mm),the part of the iris which joins
with the ciliary body.
• During blunt trauma, damage to the iris occurs most
commonly at the iris root, where the iris rips away from the
ciliary body(iridodialysis)

7. Macropscopic appearance
•Anterior surface of iris : is divided into a
ciliary zone and pupillary zone by collarette.
•Collarette represents the attachment of
pupillary membrane.

8. Ciliary Zone:
• Extends from collarette to iris root
• Some depressions or pit arranged in rows present in this area known as crypts.
• Crypts are found in two locations-
1) Central cyrpts are those present near the
collarette are relatively larger and known as
Fuchs’s crypt
2) Periphery of the iris.
Pupillary zone: this 1.6mm wide part
lies between collarette and pigmented
pupillary frill.
Pigment frill: fringe of black piment present at the pupillary margin. Represents the
anterior end of optic cup.

9. • Posterior surface of Iris:
Shows numerous radial and circular fold:
• Schwalbe’s contraction folds: radial furrows which commence
1mm from pupillary border.
• Schwalbe’s structural furrows: narrow and deep to start with,
become wide and shallow as they approach ciliary margin.
• Circular furrows: finer, cross structural furrows at regular
intervals, more marked near the pupil. They are formed due to
difference in thickness of pigmented epithelium.

10. Microscopic appearance
1. Anterior limiting layer:
• Anterior-most condensed part of iris stroma.
• Consists fibroblasts and melanocytes.
• Color of iris depends on thickness of layer and melanocyte
dispersed in this layer.
• In blue iris, this layer is thin and contains few pigment cells.
While in brown iris,it is thick and densely pigmented.
• This layer is absent in areas of crypts and very thin at contraction
furrows.

11. Microscopic structure of
iris and ciliary body

12. 2. Iris stroma:
• Forms main bulk of iris tissue and consists of loosely arranged
collagenous network with mucopolysaccharide ground substance.
Contains
• Sphincter pupillae: consists of flat bars of plain muscle fibres derived
from ectoderm. Supplied by parasympathetic fibres through III cranial
nerve, constricts the pupil.
• Dilator pupillae: lies in posterior part of stroma of ciliary zone of iris.
Supplied by cervical sympathetics, dilates the pupil.
• Vessels: forms the bulk of iris stroma. Radial vessels are branches of
circulus arteriosus major. They are responsible for radial streaks seen
on anterior surface of iris. They are straight when pupil constricts and
become wavy when pupil dilates.
• Nerves: Iris nerves are unmyelinated ,however ,some nerves are
found to be enclosed by Schwann cells.
• Cells
o Pigmented cells or melanocytes are branching elements with processes
o Clump cells are round pigment cells without processes, have large
round dark pigment granules.
o Non-pigmented cells = fibroblasts, lymphocytes , macrophages

14. 3) Anterior epithelial layer:
• Anterior continuation of pigmented epithelium of retina and ciliary
body.
• Lacks melanocytes.
• Continues anteriorly upto pupillary margin as cuboidal epithelial
cells and posteriorly as pigmented epithelium of ciliary body.
• Apical portion of cuboidal cells is pigmented and joined with each
other by tight junctions.
• Muscle processes extend into stroma and give rise to 3-5 layers of
dilator pupillae muscle.

15. 4. Posterior pigment epithelium of iris:
• Anterior continuation of non-pigmented epithelium of ciliary body
• Pigment cells are columnar, joined together by tight junctions and
desmosomes, contain dark brown pigment granules.
• Pigment granules are shed from the posterior iris surface and are
dispersed in the anterior chamber. Significant pigment loss will be
evident on transillumination of the iris.

16. Ciliary body
• Middle part of uveal tract.
• Forward continuation of choroid at ora serrata

17. Parts of the ciliary body:
• In cross-section, is a triangular structure
(in the diagram it can be compared as
triangle AOI).
• Outer side of triangle (O) is attached to
sclera with suprachoroidal space in between.
• Anterior side of triangle (A) forms part of
• anterior & posterior chamber. In its middle,iris is attached.
• Inner side of triangle (I) is divided into two parts.
o Anterior part (2 mm) with finger-like processes is known as pars
plicata (corona ciliaris) and posterior smooth (5 mm temporally,
3mm nasally) is known as pars plana (orbicularis ciliaris).

18. Pars plicata :
Portion of ciliary body that contains ciliary processes.
• Finger-like projections, which extend into posterior chamber.
• Regions between ciliary processes(white color) are called
valleys of Kuhnt(grey color).
• These spaces hold suspensory ligament of lens.
• They are approximately 70 to 80 in numbers.

19. Pars plana:
• Flat or smooth part
• Terminates at ora serrata, which is the transitional zone between
the ciliary body and choroid.
• Histologically, consist of double layer of epithelial cells:
the inner(non-pigmented epithelium),which is continuous with
neurosensory retina;and the outer(pigmented epithelium),which is
continuous with retinal pigment epithelium (RPE).
• Relatively avascular zone, which is important surgically in pars
plana approach to vitreous space.
• Provide surgical access to vitreous and retina.

20. Layers of the ciliary body
1. Supraciliary lamina: outermost condensed part of stroma.
Consists of collagen fibres. Posteriorly it is a continuation of
suprachoroidal lamina and anteriorly it becomes continuous
with anterior limiting membrane of iris.
2. Stroma : consists of connective tissue of collagen and
fibroblasts embedded with ciliary muscle, vascular stroma,
nerves, pigment cells and other cells.
Ciliary muscle: non striated muscle, triangular in shape in cut
section, helps in accomodation, supplied by parasympathetic
fibres from ciliary ganglion.

21. Ciliary epithelium:
Consists of two layers-
3. Non pigmented epithelium (NPE) of ciliary body :
• Extends from iris root to ora serrata.
• Forward continuation of sensory retina which stops at ora serrata
• Cells become smaller and there is decrease in melanin granules in
cells.

23. 4. Pigmented epithelium of ciliary body:
• Forward continuation of RPE layer
• Anteriorly,continues with anterior epithelium of iris.
• Cells contain large pigment granules.

24. 5. Internal limiting membrane;
• Forward continuation of ILM layer of retina.
• It lines non-pigmented epithelial layer
• Gives origin to parts of suspensory lens ligament.

27. Ciliary processes
• Whitish finger like projection from the pars plicata
• 70-80 in number
• Site of aqueous production.
Ultrastructure:
has three basic components:
1. Network of capillaries: occupies the centre of each process,
each capillary consists of thin endothelium with false pores
lined by basement membrane, containts mural cells or
pericytes.
2. Stroma: seperates capillary network from epithelial layers,
consists of ground substance, few collagen tissue fibres and
wandering cells.
3. Two layers of epithelium: outer pigmented and inner non
pigmented epithelium. Inner pigmented epithelium containts
mitochondria, zona occludentes and lateral and surface
interdigitations.

28. CHOROID
• Thin but highly vascular membrane lining inner surface of sclera.
• Extends from anteriorly ora serrata to optic nerve posteriorly.
• Rough outer surface-attached to sclera at optic nerve and at the exit of the
vortex veins.
• Smooth inner surface-attached to retinal pigmented epithelium(RPE).
• Continuous with pia and arachnoid at optic nerve. 100-220 µm thick &
thickness is highest at macula 500- 1000 µm.
• Choroidal thickness increases in intraocular inflammation.
• Smooth configuration can be observed ophthalmoscopically in choroidal
detachment.

29. Microscopic structure of
choroid:
Divided into the following layers
histologically:
1)Suprachoroid lamina (lamina
fusca):
• Consist of collagen fibres,
fibroblasts and melanocytes.
• Potential space between sclera
and choroid known as
suprachoroidals space.
(contains long and short posterior
ciliary arteries and nerves).

30. 2. Choroidal stroma:
Unlike tissues like iris,where stroma occupies a major part of the
tissue, major bulk is made up of choriocapillaries, which are
arranged in two layers:
• Haller’s layer: outer layer of larger vessels
• Sattler’s layer: inner layer of medium vessels.
The innermost vessels are arterioles which connect with
choriocapillaries.
The outermost part next to the suprachoroidal lamina contains mainly
veins.

31. Cells:
• Melanocytes,fibrocytes,mast cells and plasma cells.
• Melanocytes are distributed heavily in outer part of the layer and
near optic disc. Among the non pigmented cells, fibroblasts are
most common.
Connective tissue:
• Collagen fibrils are dispersed in all directions and surround the
blood vessels

32. 3. Layer of Choriocapillaris:
• Consists of rich capillary network
• Nourishes pigment epithelium and outer layers of sensory retina.
• Capillary walls are fenestrated and contains pericytes.
• In embryonic life, choroid serves as an additional site for the
erythropoiesis.

33. Choroidal circulation:
• Constitutes 85% of blood circulation of eye.
• Higher than that in tissues like retina and brain.
• Blood-flow ranges from 800 to 2000 mL/min/100 g of tissue.
• Provide metabolic requirements of full retinal thickness only in
macular region.

34. 4. Bruch's membrane
•Innermost layer of choroid(lamina vitrea), 2-4mm thick.
• Lies between chorioapillaries and pigment epithelium of retina.
• Thickest near optic disc and thickness decreases towards
periphery.
• Composed of 5 layers and from internal to external, these are
o Basement membrane of the RPE
o Inner collagen layer
o Middle elastic tissue layer
o Outer collagen layer
o Basement membrane of the choriocapillaris
• Becomes thickened with age and produces hyaline excresences
called drusens.

35. Blood supply of uveal tract
• Short posterior ciliary arteries, long posterior ciliary arteries and
anterior ciliary arteries.
SHORT POSTERIOR CILIARY ARTERIES :
• Arise as two trunks from ophthalmic artery → each trunk divides
into 10 to 20 branches → enter the sclera in a ring around the
optic nerve → branch and supply the choroid in segmental
manner.

37. LONG POSTERIOR CILIARY ARTERIES:
•Two long posterior ciliary arteries enter the sclera: one nasal and
one temporal → pierce the sclera obliquely on medial and lateral
side of optic nerve → run forward in suprachoroidal space to reach
ciliary muscle without giving any branch→at anterior end of ciliary
muscle, anastomose with each other and with the anterior ciliary
arteries to form a circular blood vessel, the major arterial circle of
the iris.

38. ANTERIOR CILIARY ARTERIES:
• 7 anterior ciliary arteries are derived from muscular branches of
ophthalmic artery ( two each from arteries of superior rectus,
medial rectus, inferior rectus and only one from lateral rectus
muscle)→ reach episclera, form plexus and give branches
→pierce sclera near the limbus to enter the eye→anastomoses
with long posterior ciliary arteies to form major arterial circle of
iris
• Branches from major arterial circle enter iris and anastomoses
with each other to form minor arterial circle.

39. Venous drainage
1. Anterior ciliary veins: tributaries of muscular veins.
2. Smaller veins from sclera: scleral branches of short
ciliary arteries.
3. Venae verticosae: 4 in number, drain blood from
whole of choroid, receive small veins from optic
head

40. APPLIED ASPECTS

41. Walls of eye ball
Middle
vascular layer
Outer Fibrous
layer
Inner nervous
layer
retina
Uveal tract
Sclera & cornea
2. Ciliary
body
1.Iris
Anterior
uvea
3.choroid
Posterior
uvea

42. Thin regions - iris root & margin -
more susceptible to tearing in
injuries

43. Aniridia
• Absence of iris, mostly
bilateral, transmitted as an
autosomal dominant trait
or occurs sporadically.
• Can be traumatic as well.
The ciliary villi and the lens
are visible under slit lamp
retro-illumination.

44. Uveal coloboma
-A condition where a portion of the structure is missing due to
incomplete fusion of embryonic optic cup at 6th week of
pregnancy.
Typical coloboma:
Located inferonasally in the
region of closure of embryonic
fissure.
Complete coloboma:
Extends from pupil to optic
nerve Includes retina,
choroid, ciliary body and
iris.
Incomplete coloboma:
Involves the iris alone, or iris
and ciliary body, or iris,
ciliary body & part of
choroid.

45. Atypical coloboma
- Occasionally found in other positions i.e. not related to
fissure closure
- It is usually incomplete
The congenital iris coloboma is
located medially /& inferiorly.
The pupil merges with the
coloboma without any sharp
demarcation.

47. Heterochromia
• Impaired development of the pigmentation of the iris can
lead to a congenital difference in coloration between the
left and the right iris
• One iris containing varying pigmentation is referred to as
iris bicolour
• Isolated heterochromia is not necessarily clinically
significant, yet it can be sign of abnormal change. The
following are differentiated:
01. Fuchs’ heterochromic cyclitis Recurrent iridocyclitis with
precipitates on posterior surface of the cornea without
formation of posterior synechiae. The eye is free of external
irritation and often associated with complicated cataract and
glaucoma.

48. 02. Sympathetic heterochromia In unilateral
impairment of the sympathetic nerve supply,
the affected iris is significantly lighter.
Heterochromia with unilaterally lighter
pigmentation occurs in iridocyclitis, acute
glaucoma and hyphema.
03. Melanosis of the iris This refers to dark
pigmentation of one iris.

49. • Heterochromia
Iridium Color of
one iris differs
from the other
• Heterochroma
Iridis One sector
of iris differs
from the
remaining iris

50. Corectopia
• Displacement of
pupil
• Bilateral and
symmetric
• A/w ectopia lentis,
and the lens and
pupil are commonly
dislocated in opposite
directions

51. Polycoria
• More than one
opening in the iris
• Result of local
hypoplasia of iris
stroma and
pigment
epithelium

52. Iridodialysis
• Dehiscence of iris from
the ciliary body at its
root
• D- shaped pupil
• Can cause Uniocular
diplopia and glare
• May be asymptomatic
when covered by upper
lid

53. • Traumatic Aniridia ie 360 degree Iridodialysis, can also occur in
which Scleral Fixating Iris Lens is used.

54. Inflammation
Can be classified according to the various
portions of the globe:
Anterior uveitis (IRITIS)
Intermediate uveitis (CYCLITIS)
Posterior uveitis (CHOROIDITIS). However, some
inflammations involve the middle portions of
the uveal tract such as IRIDOCYCLITIS or
PANUVEITIS.

55. Anatomical classification of uveitis

61. Posterior
synechiae
Cataract Glaucoma
due to PAS
Band
Keratopathy
Complications of Uveitis

62. Iris Nodules

63. Primary Epithelial
Cyst
Primary Stromal
Cyst

64. Implantation cysts
Pearl cyst Serous cyst

65. Swellings:
Inflammatory:
• Koeppe’s and Busacca's nodules in Granulomatous
Uveitis.
• FB Granuloma.
• Juvenile Xanthograuloma.
Brushfield spots
Lisch nodules
Neoplasms:
• Benign: Naevus, Leiomyoma, Adenoma of the IPE (Iris
Pigment Epithelium), Neurofibroma, Hemangioma.
• Malignant:
–Primary : Iris melanoma
–Secondaries : extension from CB melanoma, leukemic
deposits.

66. Koeppe's and Busacca's nodules
Busacca’s nodules: on the surface
of iris. Aggregates of epithelioid
cells & mononuclear cells
Koeppe’s nodules: at pupillary
margin

67. Brushfield spots in Down syndrome

68. Lisch nodules in NF1
Benign iris hamartomas

69. Next PG activity
Date: 09/12/2020
Case presentation: Fungal Corneal Ulcer
Presenter: Dr Rajiv
Moderator: Dr Banait Sir
Conductor: Dr Archana Ma’am
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