The uvea consists of the iris, ciliary body, and choroid. It develops from both neuroectoderm and mesoderm. The iris controls the pupil size and appears by 9 weeks gestation. The ciliary body produces aqueous humor and appears by 9 weeks. The choroid supplies the outer retina and appears by 5 months gestation. The uvea contains muscles, epithelia, and vasculature. It is susceptible to inflammation and various congenital anomalies that can affect its structure and function.

1. Anatomy of Uvea
Dr.Sameeksha Agrawal

2. Introduction
• UVEA constitutes- middle vascular coat
• 3 parts- a)iris
b)ciliary body
c)choroid
• Developmentally,structurally and functionally- indivisible
• Color varies from light blue to dark brown

3. Embryology
IRIS-
• Both layers of epithelium derived from marginal region of optic cup
(neuroectoderm)
• Sphincter and dilator pupillae- anterior epithelium (neuroectoderm)
• Stroma and vessels- vascular mesoderm

4. Continued
CILIARY BODY
• Both Epithelium from neuroectoderm
• Ciliary processes from ciliary epithelium
• Stroma and blood vessels – mesoderm

5. Milestones
• 9TH WEEK GESTATION- ciliary body appears
• 12TH WEEK GESTATION- sphincter pupillae appears
• 5TH MONTH- all layers of choroid seen
- iris fully developed
• 6TH MONTH- dilator muscle begins to form, sphincter muscle is fully
formed
• POSTNATAL PERIOD- dilator muscle fully formed by 5 years, iris stromal
pigment develops after birth

6. Iris
• Anterior most part
• Avg diameter- 12mm,
thickness- 0.5mm
• In centre an aperture of
3-4mm- PUPIL
• Thinnest at its root-
tears away easily on
blunt trauma-
IRIDODIALYSIS
• Divides space into
anterior and posterior
chamber

7. Macroscopic structure
TWO SURFACES
A)ANTERIOR SURFACE
• Collarette- zigzag line, 2mm from pupil, thickest, represents attachment of
pupillary membrane
• Divides surface into-
a) CILIARY ZONE- c/b
 Radial streaks- Due to underlying radial vessels
 Crypts- Depressions where suoerficial layers of iris is missing
peripheral-near the iris
central- near collarette
 Contraction furrows- faints lines outside collarette

8. Continued
b) PUPILLARY
ZONE-
 Between collarette
and pigmented frill
 Pigmented frill-
black pigment at
pupillary margin
-
represents ant end
of optic cup

9. Continued
B)POSTERIOR SURFACE- dark brown/black
Contains-
A) Schwalbe’s contraction folds- 1 mm from pupillary border, little radial furrows
B) Schwalbe’s structural furrows- 1.5 mm from pupillary border. Narrow and deep
to start with and become wide and shallow as they approach ciliary margin
C) Circular furrows- finer then radial furrows. Crosses structural furrows at
regular intervals. More marked near the pupil and formed due to difference in
thickness of pigmented epithelium.

10. Microscopic structure
FOUR LAYERS-
a)Anterior limiting layer- consists melanocytes and fibroblasts
Previously called endothelial layer
• Colour of iris depends on this layer
• Blue iris- thin layer and few pigment cells
• Brown iris- thick and doubly pigmented
b) Iris stroma-
• Forms main bulk
• Consists of collagenous tissue with mucopolysaccharide
• Structures embedded-

11. Continued
 Sphincter pupillae- 1 mm broad circular band in pupillary area
derived by ectoderm
supplied by parasympathetic fibres by 3rd nerve
constricts pupil
 Dilator pupillae- lies in posterior part of ciliary zone
supplied by cervical sympathetics
dilates pupil

12. Continued
Anterior epithelial layer
 anterior continuation of pigment epithelium of retina and ciliary body
 Lacks melanocytes
 Basal processes- give rise to dilator pupillae
D)Posterior pigmented epithelial layer
 Anterior continuation of non pigmented epithelium of ciliary body
 Derived from internal layer of optic cup
 Forms pigmented frill

15. FUNCTIONS OF IRIS
• Controls amount of light entering the eye through pupil
• Defines eye colour
• Control depth of field
• Source of blood ocular to tissues

16. Ciliary Body
• Forward continuation of choroid at ora serrata
• Triangular in cut section, ant side of its form part of angle , in middle attached
to iris and outer part lies against sclera
• Triangle – two parts
a) Anterior part- ciliary processes (pars plicata) 2-2.5mm
b)Posterior part- smooth (pars plana) 5mm wide temporally & 3mm nasally

18. Microscopic Structure
1.SUPRACILIARY LAMINA- outermost part
 Consist of pigmented collagen fibres
 Posteriorly continuation of suprachoroidal lamina, ant continous with anterior
limiting membrane

19. Continued
2.STROMA-
Consists
 Ciliary muscle- non striated, triangular in cut section, 3 parts
 Longitudnal/meridional fibres- origin from scleral spur, inserts into
suprachoroidal lamina
 Circular fibres- in inner portion, nearest to lens
 Radial fibres- obliquely placed
Actions - slacken suspensory ligament thus helps in accomodation
circular fibres- directly as sphincter
nerve supply- parasym. fibres from ciliary ganglion

20. Continued
3)Layer of pigmented epithelium- forward continuation of RPE
 Anteriorly continues to anterior epithelium of iris
4)Layer of non pigmented epithelium- forward continuation of sensory retina
 Continues anteriorly with posterior pigmented epithelium of iris
5)Internal limiting membrane-lines NPE
 Forward continuation of internal limiting membrane of retina

21. Ciliary Processes
• Finger like projections from pars plicata
• 70-80 in number, 2mm long 0.5mm
diameter
• Site of aqueous production
ULTRASTRUCTURE
1)Network of capillaries- in the centre
• Has endothelium with fenestrae
2)Stroma of ciliary processes- thin,
separates capillaries from epithelium
3)Epithelium-two layered with apical
apposition

22. Functions of ciliary body
• Site of aqueous humour production
• Maintenance of IOP
• Constitutes blood aqueous barrier
• Accommodation

23. Choroid
• Posterior most part
• Extension- optic disc to ora serrata
• Inner surface- smooth, brown and in contact with RPE
• Outer surface-rough and in contact with sclera
• Thickness- posteriorly 0.22mm
anteriorly 0.10mm

24. Microscopic structure
1) Suprachoroidal lamina- lamina fusca
• Thin layer, continues anteriorly with supraciliary lamina of ciliary body
• Suprachoroidal space- contains long and short posterior ciliary arteries and
nerves
2) Stroma – plenty of pigmented cells, macrophages, mast and plasma cells
• Vessels- form the bulk
• Arranged in two layers- outer consisting of large vessels(hallers layer), inner
of medium vessels ( sattlers layer)

25. Continued
3) choriocapillaris- rich capillary network
• Supplies pigment epithelium and outer layers of sensory retina
• Few anastomosis with CRA
4)Basal lamina- bruch’s membrane
• Innermost layer
• Between choriocapillaris and RPE
• Electron microscopy- basement membrane of RPE, inner collagen, middle
elastic and outer collagen and basement membrane choriocapillaris

27. FUNCTIONS OF CHOROID
• BLOOD SUPPLY TO OUTER LAYERS OF RETINA
• ASSIST IN THE CONTROL OF INTRAOCULAR PRESSURE
• PIGMENT ABSORBS EXCESS LIGHT SO AVOIDING REFLECTION

28. BLOOD SUPPLY UVEAL TRACT
1.SHORT POSTERIOR CILIARY ARTERIES
• Branches of ophthalmic artery
• Divides into 10-20 branches, pierce sclera around optic nerve
• Supply choroid in segmental manner
2) LONG POSTERIOR CILIARY ARTERIES
• Two in number- nasal and temporal
• Pierce sclera
• Anastomose with anterior ciliary arteries- form major arterial circle supply
ciliary body
3)ANTERIOR CILIARY ARTERIES
• From muscular arteries
• 7 in number
• 2 each SR,IR,MR and 1 from LR
• Anastomse with LPCA

31. VENOUS DRAINAGE
Vena verticosae- 4 in no.
Drain whole of choroid

32. UVEITIS ( APPLIED ASPECTS)
• Inflammation of uveal tract
• Usually U/L
• CLASSIFICATION-
1. ANTERIOR- iritis, iridocyclitis
2. INTERMEDIATE- cyclitis, pars planitis
3. POSTERIOR- retinitis, chorioretinits
4. PANUVEITIS

34. CONGENITAL ANOMALIES
1.HETEROCHROMIA IRIDUM
2.POLYCORIA- more then one pupil
3.CORECTOPIA- abnormally eccentric pupil

35. Continued
4. ANIRIDIA- abscence of iris
• o/e- a narrow rim of iris tissue behind sclera seen oftenly
• zonules of lens and ciliary processes often visible
5. PERSISTENT PUPILLARY MEMBRANE-
• Persistent part of ant vascular sheath of lens
• Attached to collarate

36. Continued
5.COLOBOMA UVEA- defect in tissue
• incomplete closure of the embryonic fissure during
development
• Associations- micropthalmia, cataract, glaucoma,
refractive error, CHARGE syndrome, colobomas of
lids/lens/retina
• Mutation PAX2 gene
• Types –
• a) typical – inferonasal quadrant, pupil is pear shaped
Choroidal coloboma- oval, rounded apex towards disc,
vessels traversing disc, disc may be involved
b)atypical- elsewhere, iris involved
etiology- intrauterine inflammations

38. Continued
CYST OF IRIS- congenital cyst may arise from
a)stroma
b)pigment epithelium

39. BRUSHFIELD SPOTS IN DOWNS SYNDROME
LISCH NODULES IN NF1

40. Thank you