A complete Detail Review of Anatomy of Uvea and Physiology of uvea

1. UVEA
ANATOMY AND PHYSIOLOGY
BY
VIPIN G
M.OPTOM

2. UVEA
Uvea is Greek word meaning grapes
 It is known as middle vascular coat of
eyeball
Anterior to posterior it can be divided into
three parts
Iris
Ciliary body
Choroid

3. IRIS
Anterior part of the uveal tract
Center of iris has an aperture3-4mm
called pupil
At periphery it attached to anterior
surface of ciliary body
Divides the space between cornea
and lens into anterior chamber and
posterior chamber

4. Average diameter of iris is 10 to 11mm
Thickness of iris root is approximately
0.5mm
Thinnest at roots and tears away easily
from attachment to ciliary body -
iridodialysis

5. ANTERIOR SURFACE
Divided into ciliary and pupillary zone
by zigzag line called collarette
 CILIARY ZONE
• Crypts
• Contraction furrows
• Radial streaks
MACROSCOPIC APPEARANCE

6.  PUPILLARY ZONE
• Lies between collarette and
pigmented pupillary frill
• It is relatively smooth and flat

8. POSTERIOR
SURFACE
Posterior surface of iris is much more
uniform
Posterior surface is darker than anterior
surface
• Schwalbe’s contraction folds
• Schwalbe’s structural furrows
• The circular furrows

9. MICROSCOPIC
STRUCTURE
The iris consists of four layers, which form
anterior to posterior
• Anterior limiting layer
• Iris stroma
• Anterior epithelial layer
• Posterior pigmented epithelial layer

10. Anterior limiting layer
Stroma
Condensed part of stroma
Consists of melanocytes and fibroblasts
Determines the colour of iris
Main bulk of iris
Loosely arranged collagenous network
Contains sphincter pupillae, dilator
pupillae, vessels and nerves
Cells- fibroblast, melanocytes, clump
cells ,mast cells

11. SPHINCTER PUPILLAE
Circular muscle composed of smooth muscle
It encircles the pupil and is located in the pupillary zone of stroma
It is thicker than dilator pupillae
It consist of spindle shaped cells ,that oriented towards pupillary margin so
contraction of sphincter causes pupil to constrict
It innervated by parasympathetic system

12. It extend from iris root to pupil
Because of radial arrangement of muscles, contraction
of dilator pupillae muscle pulls the pupillary margin
towards ciliary body ,dilating the pupil.
It is innervated by sympathetic system
DILATOR
PUPILLAE

13. • VESSELS OF IRIS
• PIGMENT CELLS

14. ANTERIOR EPITHELIAL LAYER
Anterior continuation of pigment epithelium of ciliary body
Lacking of melanocytes
POSTERIOR PIGMENTED EPITHELIAL LAYER
Anterior continuation of non pigmented epithelium of ciliary body which in turn is
continuation of the sensory retina

15. FUNCTIONS OF IRIS
 CONTROLS AMOUNT OF LIGHT ENTERING THE EYE THROUGH PUPIL
 CONTROL DEPTH OF FIELD
 SOURCE OF BLOOD OCULAR TISSUES

16. It is located between the iris and choroid
Middle part of vascular coat of eyeball
Triangular in shape
CILIARY BODY

17. Outside of triangle with sclera with
suprachoroidal space in between
Anterior side of triangle forms part of
anterior and posterior chamber
In middle-iris
Inner side of triangle divided into
Pars plicata-
anterior
Pars plana-
posterior
PARTS OF
CILIARY BODY

18. MICROSCOPIC STRUCTURE
SUPRACILIARY LAMINA
Outermost condensed part of stroma
Consists of pigmented collagen fibrils
Continuation of suprachoroidal lamina
Anteriorly continues with anterior limiting membrane of iris.
STROMA OF CILIARY BODY
Consists of collagenous connective tissue and fibroblast
Ciliary muscles, vessels, nerves, cells are embedded

19. Longitudinal or meridional fibres
Oblique or radial fibres
Circular fibres
Contraction of ciliary muscles , especially
longitudinal and circular fibres pulls the ciliary body
forward during accommodation .
CILIARY MUSCLES

20. MICROSCOPIC STRUCTURE OF IRIS AND CILIARY BODY

21. LAYER OF PIGMENTED EPITHELIUM
 forward continuation of RPE
Anteriorly continues with anterior epithelium of iris
LAYER OF NON PIGMENTED EPITHELIUM
 mainly consists of low columnar and cuboidal cells
Continues anteriorly with posterior pigmented epithelium of iris
INTERNAL LIMITING MEMBRANE
Lines non pigmented epithelium
Forward continuation of internal limiting membrane of retina

22. It is whitish finger like projection from
pars plicata part of ciliary body
70 to 80 in number
Zonules of lens are inserted in this
valleys
Each about 2mm long and 0.5mm in
diameter
Site of aqueous production
CILIARY
PROCESSES

23. FUNCTIONS OF CILIARY BODY
 Site of aqueous humour production Maintenance of IOP
 Constitutes blood aqueous barrier
 Accommodation
 Eicosanoids are synthesized in ciliary body

24. CHOROID
Posterior portion of middle vascular coat
Thin and highly vascular membrane
Inner surface – smooth ,lies in contact with RPE
Outer surface-rough and attached with sclera

25. MICROSCOPIC STRUCTURE
SUPRACHOROIDAL LAMINA(LAMINA FUSCA)
Consists of collagen fibres, fibroblast, and melanocytes
Space between sclera and choroid known as suprachoroidal space

26. CHOROIDAL STROMA
Contains loose connective tissue, vessels , nerves
Cells-melanocytes,fibroblast,macrophages,mast cells,plasma cells
Haller’s layer- layer of large vessels
Sattler’s layer- layer of medium vessels
LAYER OF CHORIOCAPILLARIES
Nourishes pigmented epithelium and outer layer of retina
 receives blood from vessels of stroma

27. BRUCH’S MEMBRANE
 Innermost layer of choroid
2 to 4µm in thickness

28. FUNCTIONS OF CHOROID
 BLOOD SUPPLY TO OUTER FOUR LAYERS OF RETINA
 MODULATION OF VASCULARISATION
 REGULATE RETINAL HEATASSIST IN THE CONTROL OF
INTRAOCULAR PRESSURE .
 PIGMENT ABSORBS EXCESS LIGHT SO AVOIDING REFLECTION

29. BLOOD SUPPLY
Uveal tract is supplied by three sets of arteries
Short posterior ciliary arteries
Long posterior ciliary arteries
Anterior ciliary arteries
VENOUS DRAINAGE
Small veins which drain blood from iris , ciliary body , choroid join to
form vortex veins

30. FUNCTIONS OF UVEA
 It is the source of blood flow to the ocular tissues
 It is the site of aqueous humor production and maintenance of intraocular
pressure
 It constitutes the blood aqueous barrier
 Musculature of the ciliary body play role in the process of accommodation
 Eicosanoids are synthesized in the iris and ciliary body

31. Reference
Comprehensive ophthalmology
Anatomy and physiology of eye – A k Khurana
Uvea Article in NCBI author – Paul E.Miller

32. THANK YOU