Detailed presentation of anatomy of Uvea

1. ANATOMY OF
UVEA
By
Dr Satish S Hadimani
Dept of shalakya tantra
SGR Ayurved Mahavidyalaya,
Solapur

3. UVEA constitutes- middle vascular coat
 3 parts-
INTRODUCTION
Uvea
Iris
Ciliary
body
Choroid

4.  Developmentally, structurally and functionally-
indivisible
 color varies from light blue to dark brown

5. 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

6. Iris
Anterior
chamber
Posterior
chamber

8. MACROSCOPIC
APPEARANCE
TWO SURFACES
1)ANTERIOR SURFACE
Collarette- zigzag line, 2mm from pupil, thickest,
represents attachment of pupillary membrane
 Divides surface into-
a)CILIARY ZONE- c/b
 Radial streaks
 Crypts- peripheral-near the iris
central- near collarette
 Contraction furrows- faints lines outside collarette
b) PUPILLARY ZONE-
 Between collarette and pigmented frill
 Pigmented frill- black pigment at pupillary margin
-represents ant end of optic cup

11. 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
C) Circular furrows- finer then radial furrows

12. Microscopic structure
• Anterior limiting layer-a)
• Iris stroma-b)
• Anterior epithelial layerc)
• Posterior pigmented
epithelial layerd)

13. 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-
 Sphincter pupillae- 1 mm broad circular band in pupillary
area
derived by ectoderm
supplied by parasympathetic fibres by
3rd nerve

14. Dilator pupillae- lies in posterior part of ciliary
zone supplied by cervical sympathetics dilates
pupil
vessels- form bulk of stroma
radial vessels- branches of circulous arteriosis
major
Pigment cells- melanocytes
Lymphocytes, fibroblast and macrophages

15. C) 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

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

20. 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

22. MICROSCOPIC STRUCTURE
1)
• Supraciliary lamina-
2)
• Stroma
3)
• Layer of pigmented epithelium-
4)
• Layer of non pigmented epithelium-
5)
• Internal limiting membrane

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

24. 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

25. Vascular stroma- major arterial circle lies
 Formed by anastomosis of long and short PCA
 Supplies iris and ciliary body
3)Layer of pigmented epithelium- forward continuation of
RPE
 Anteriorly continues to pigmented epithelium of iris
4)Layer of non pigmented epithelium- forward
continuation of sensory retina
 Continues anteriorly with pigmented epithelium of iris
5)Internal limiting membrane-lines NPE

26. 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

27. FUNCTIONS OF CILIARY BODY
 Site of aqueous humour production
 Maintenance of IOP
 Constitutes blood aqueous barrier
 Accommodation
 Eicosanoids are synthesised in ciliary
body

29. 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

31. MICROSCOPIC STRUCTURE
1)
• Suprachoroidal lamina-
2)
• Stroma
3) • Choriocapillaris
4)
• Basal lamina-

32. 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)
3) Choriocapillaris- rich capillary network

33. 4)Basal lamina- bruch’s membrane/lamina vitrae
 Innermost layer
 Between choriocapillaris and RPE
 Electron microscopy- basement membrane of RPE,
inner collagen, middle elastic and outer collagen and
basement membrane choriocapillaris
 With increasing age- produces hyaline excresences
known as druscens

35. FUNCTIONS OF CHOROID
 BLOOD SUPPLY TO OUTER FOUR LAYERS OF
RETINA
 MODULATION OF VASCULARISATION
 REGULATE RETINAL HEAT
 ASSIST IN THE CONTROL OF INTRAOCULAR
PRESSURE
 PIGMENT ABSORBS EXCESS LIGHT SO
AVOIDING REFLECTION

36. 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
 Circulous arterious major and minor

42. VENOUS DRAINAGE
1)Anterior ciliary veins- tributaries of muscular veins
2)Smaller veins from sclera- carry blood only from
sclera and not from choroid
3)Vena verticosae- 4 in no.
Drain whole of choroid