The document discusses the anatomy and physiology of the uvea, which consists of the iris, ciliary body, and choroid. It describes the layers, muscles, blood supply, and functions of each part. The iris controls the pupil size and divides the eye into anterior and posterior chambers. The ciliary body produces aqueous humor and contains muscles that allow for accommodation. The choroid provides blood supply to the outer retina and regulates heat and light absorption. Overall, the uvea is the middle vascular layer that nourishes ocular tissues and helps control intraocular pressure and accommodation.

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