Ppt for pgs

2. INTRODUCTION
UVEA :
• constitutes the 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
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. • Both Epithelium from neuroectoderm
• Ciliary processes from ciliary epithelium
• Stroma and blood vessels – mesoderm
EMBRYOLOGY - CILIARY BODY

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 (slightly nasal) an aperture of 3-4mm- PUPIL
• Thinnest at its root (at middle of anterior surface of ciliary body)-
tears away easily on blunt trauma- IRIDODIALYSIS
• Divides space into anterior and posterior chamber

7. MACROSCOPIC
APPEARANCE -
TWO SURFACES of
Iris
A. ANTERIOR SURFACE
• Collarette-
zigzag line, 2mm from pupil, thickest,
represents attachment of pupillary
membrane
• Divides surface into-
a) CILIARY ZONE-
Radial streaks
Crypts – peripheral - near the iris
central - near collarette
Contraction furrows- faints lines outside collarette
b) PUPILLARY ZONE-
Between collarette and pigmented frill - about 1.6mm
Pigmented frill - black pigment at pupillary margin -represents ant end of optic cup

9. MACROSCOPIC APPEARANCE -
TWO SURFACES of Iris
B. POSTERIOR SURFACE-
• Dark brown/black colour
• 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

10. A. Anterior limiting layer -
• Consists of 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
MICROSCOPIC STRUCTURE - FOUR
LAYERS of Iris

11. 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
• constricts pupil
• 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 peculiarities- absence of IEL(Internal Elastic lamina) & non fenestrated capillary endothelium
MICROSCOPIC STRUCTURE - FOUR
LAYERS of Iris

12. MICROSCOPIC
STRUCTURE -
FOUR LAYERS of
Iris
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

13. FUNCTIONS OF IRIS
• CONTROLS AMOUNT OF LIGHT ENTERING THE EYE THROUGH PUPIL
• DEFINES EYE COLOUR
• CONTROL DEPTH OF FIELD
• SOURCE OF BLOOD OCULAR TISSUES

14. • 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
CILIARY BODY

15. 1. SUPRACILIARY LAMINA - outermost part
• Consist of pigmented collagen fibres
• Posteriorly continuation of suprachoroidal lamina,
ant. continous with anterior limiting membrane
2. STROMA - Consists
• Ciliary muscle - non striated, triangular in cut
section, 3 parts -
I. Longitudnal/meridional fibres- origin from scleral
spur, inserts into suprachoroidal lamina
II. Circular fibres- in inner portion, nearest to lens
III. Radial fibres- obliquely placed
• Actions - slacken suspensory ligament thus helps in
accomodation circular fibres- act directly as
sphincter
• Nerve supply- parasym. fibres from ciliary ganglion
• Vascular stroma - major arterial circle lies
CILIARY BODY -
MICROSCOPIC STRUCTURE

16. 3. LAYER OF PIGMENTED
EPITHELIUM -
• forward continuation of
RPE
• Anteriorly continues to
anterior pigmented
epithelium of iris
4. LAYER OF NON
PIGMENTED EPITHELIUM
-
CILIARY BODY -
MICROSCOPIC STRUCTURE

17. 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 –
CILIARY BODY -
MICROSCOPIC STRUCTURE

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

19. 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

20. 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
• Supplies pigment epithelium and outer layers of sensory retina
• Few anastomosis with CRA
CHOROID - MICROSCOPIC
STRUCTURE

21. 4. Basal lamina - bruch’s membrane/lamina vitrae
• Innermost layer • Between choriocapillaris and RPE
• Approx. 2 to 4 mm in thickness
• Electron microscopy- 5 layers
1. Basement membrane of RPE
2. inner collagen
3. middle elastic
4. outer collagen
5. basement membrane choriocapillaris
• With increasing age- produces hyaline excresences known as drusens
CHOROID - MICROSCOPIC
STRUCTURE

22. 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

23. 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
BLOOD SUPPLY UVEAL TRACT -
Arterial

24. 1. Anterior ciliary veins -
tributaries of muscular
veins
2. Smaller veins from sclera -
carry blood only from
sclera and not from
choroid
3. Venae verticosae - 4 in no.
Drain whole of choroid
BLOOD SUPPLY
UVEAL TRACT –
Venous drainage

26. • Inflammation of uveal tract
• Usually U/L
• CLASSIFICATION-
A. ANATOMICAL
• ANTERIOR- iritis, iridocyclitis
• INTERMEDIATE- cyclitis, pars planitis
• POSTERIOR- retinitis, chorioretinits
• PANUVEITIS
B. PATHOLOGICAL
• GRANULOMATOUS
• NON GARNULOMATOUS
UVEITIS

27. CONGENITAL ANOMALIES
1. HETEROCHROMIA -
• Iridum
• Iridis
2. POLYCORIA - more then one pupil
3. CORECTOPIA - abnormally eccentric pupil

28. CONGENITAL
ANOMALIES
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

29. 6. 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 and fibrovascular sheath
persistence
CONGENITAL ANOMALIES

30. 7. CYST OF IRIS- congenital cyst may arise
from
a) stroma- derived from ectopic cells of surface
ectoderm of developing lens
b) pigment epithelium- due to failure of fusion of
two layers of optic vesicle
CONGENITAL ANOMALIES

31. 7. Abnormal neural crest cell proliferation
Iridocorneal Endothelial Syndrome
I. Progressive iris atrophy
II. Iris naevus (Cogan-Reese) syndrome
III. Chandler syndrome
CONGENITAL ANOMALIES

32. IV. BRUSHFIELD SPOTS IN DOWNS SYNDROME
V. LISCH NODULES IN NF1
CONGENITAL ANOMALIES

33. THANK YOU