This document provides an overview of the anatomy of the eye. It describes the three layers of the uveal tract - the iris, ciliary body, and choroid. The iris is the circular structure that controls the size of the pupil and contains two types of muscles. The ciliary body is located behind the iris and produces aqueous humor. It contains the ciliary muscle which helps with accommodation. The choroid is the highly vascular layer located behind the retina that provides blood flow to the outer retina.

1. ANATOMY OF
EYE
Dr Sparsha S K
1st yr shalakya tantra
AAMC

2. UVEAL TRACT
A. Iris
B. Ciliary body
C. Choroid
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3. IRIS

4. anterior most part
 thin circular disc
 In its centre is an aperture of about 4
mm diameter called pupil which regulates
the amount of light reaching the retina.
At periphery, the iris is attached to the
middle of anterior surface of the ciliary
body.
 It divides the space between the cornea
and lens into anterior and posterior
chambers
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5. Diameter 12 mm
Circumference 38 mm
Thickness 0.6mm -collarette
0.5mm- root
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6. COLOUR
Pigment in the melanocytes
Iris is brown - melanocytes are
profuse and well pigmented
Blue iris there is a paucity of
melanocytes and while the longer
wavelengths of light are absorbed, the
shorter wavelengths in the blue region
of the spectrum are back-scattered or
reflected.
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7. MACROSCOPIC
APPEARANCE
Ciliary zone.
 series of radial streaks due to underlying
radial blood vessels and crypts
Crypts are arranged in two rows
the peripheral - near the iris root
the central -near the collarette.
Pupillary zone.
This lies between the collarette and
pigmented pupillary frill
 relatively smooth and flat 3/1/20XX 7

8. MICROSCOPIC
STRUCTURE
1) Anterior limiting layer
2) Iris stroma
3) Anterior epithelial layer
4) Posterior pigmented
epithelial layer
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9. 1)Anterior limiting layer
Consists of melanocytes and
fibroblasts.
Deficient in the areas of crypts.
Definitive colour of the iris depends on
this layer..
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2)Iris stroma
loosely arranged collagenous network in
which are embedded the sphincter pupillae
muscle, dilator pupillae muscle, vessels,
nerves, pigment cells and other cells which
include lymphocytes, fibroblasts,
macrophages and mast cells.
Sphincter pupillae muscle
forms one millimetre broad circular band
in the pupillary part
constricts the pupil.
Dilator pupillae muscle
lies in the posterior part of stroma of the
ciliary zone of iris.
dilates the pupil

10. 10
3)Anterior epithelial layer
It is anterior continuation of the pigment
epithelium of retina and ciliary body.
This layer gives rise to the dilator pupillae muscle
4)Posterior pigmented epithelial layer
anterior continuation of the nonpigmented epithelium of
ciliary body
. At the pupillary margin, it forms the pigmented frill

11. FUNCTIONS
 Controlls the amount of light entering the eye through pupil
 Defines eye colour
 Controlls depth of field
 Source of blood ocular to tissues
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12. CILIARY BODY
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13.  thickened part of the uveal tract lying
just posterior to the corneal limbus.
 It is continuous anteriorly with the iris
and posteriorly with the choroid.
 It suspends the lens and helps it in
accommodation for near vision.
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14. In cut-section
triangular in shape
anterior side - angle of anterior and posterior chambers
 middle - iris
 outer side - against the sclera with a suprachoroidal space
 inner side
i. pars plicata The anterior part (about 2 mm) having finger-like ciliary
process
ii. pars plana the posterior smooth part (about 4 mm)
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15. MICROSCOPIC STRUCTURE
1) Supraciliary lamina.
2) Stroma of the ciliary body
3) Layer of pigmented epithelium
4) Layer of nonpigmented epithelium
5) Internal limiting membrane
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16. Supraciliary lamina
 outermost layer of the ciliary body
 lies adjacent to the sclera.
 It is composed of loose connective tissue with collagen strands, fibroblasts,
and melanocytes.
 supraciliary lamina acts as a potential space.
 Thus it also helps aqueous humor to exit by the unconventional pathway.
 Ciliary body detachment occurs through this
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17. Stroma
It consists of connective tissue of collagen and fibroblasts.
Embedded in the stroma are ciliary muscle, vessels, nerves, pigment and other cells.
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Ciliary muscle occupies most of the outer part of ciliary body.
In cut section it is triangular in shape.
It is a nonstriated muscle having three parts:
I. Longitudinal or meridional fibres which help in aqueous
outflow;
II. Circular fibres which help in accommodation;
III. Radial or oblique fibres act in the same way as the
longitudinal fibres

18. Layer of pigmented
epithelium.
forward continuation of the
retinal pigment epithelium.
 Anteriorly - continuous with
the anterior pigmented
epithelium of the iris
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19. Layer of nonpigmented
epithelium
 low columnar or cuboidal cells,
and is the forward continuation of
the sensory retina.
It continues anteriorly as the
posterior (internal) pigmented
epithelium of the iris.
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20. Internal limiting
membrane
It is the forward continuation of
the internal limiting membrane of
the retina. It lines the non
pigmented epithelial layer.
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21. Ciliary processes
finger-like projections from the pars plicata part
of the ciliary body.
70–80 in number.
Each process is about 2 mm long and 0.5 mm in
diameter.
white in colour.
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22. Structure.
Each process is lined by two layers
of epithelial cells.
The core of the ciliary process
contains blood vessels and loose
connective tissue.
These processes are the site of
aqueous production
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23. FUNCTIONS
 Site of aqueous humour production
 Maintenance of IOP
 Constitutes blood aqueous barrier
 Accommodation
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24. CHOROID
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25. Posterior most part
Extends from optic disc to the ora
serrata.
 thickest at the posterior pole (about
0.22 mm) and gradually thins anteriorly
(about 0.1 mm).
Inner surface is smooth, brown and lies
in contact with pigment epithelium of the
retina.
Outer surface is rough and lies in
contact with the sclera.
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26. Microscopic structure
1) Suprachoroidal lamina
2) Stroma of the choroid
3) Basal lamina.
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27. Suprachoroidal lamina
It is a thin membrane of condensed
collagen fibres, melanocytes and
fibroblasts.
continuous anteriorly with the
supraciliary lamina.
The potential space between the
membrane and sclera is called
suprachoroidal space which contains long
and short posterior ciliary arteries and
nerves.
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28. Stroma
It consists of loose collagenous tissue with some
elastic and reticulum fibres.
contains pigment cells and plasma cells.
Its main bulk is formed by vessels which are
arranged in three layers. From without inwards these
are
a) layer of large vessels (Hailer’s layer),
b) layer of medium vessels (Sattler’s layer)
c) layer of choriocapillaris
which nourishes the outer layers of the retina
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29. Basal lamina
Bruch’s membrane
Lines the layer of choriocapillaris
Lies in approximation with pigment epithelium of the retina
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30. FUNCTIONS
 Blood supply to outer layer of retina
 Assist in the control of IOP
 Pigment absorbs excess light so avoiding reflection
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31. BLOOD SUPPLY OF
UVEAL TRACT
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Arterial supply
1) Short posterior ciliary
arteries.
2) Long posterior ciliary
arteries.
3) Anterior ciliary arteries.

32. A series of small veins which
drain blood from the iris,
ciliary body and choroid join
to form the vortex veins
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Venous drainage

33. Reffernce
 Comprehensive Ophthalmology by AK Khurana
 BD Chaurasia’s Applied Dissection and Clinical Head and
Neck 8th edition
 Clinical Anatomy of the Eye by Richard S. Snell 2nd edition
 Wolff’s anatomy of eye and orbit 8th edition
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