basic of vitreous

1. ANATOMY OF VITREOUS
Dr Anupama Manoharan
JR Dept. of ophthalmology
UGMCH OOTY (TN)

6. PRIMARY VITREOUS STAGE
•primary vitreous body begins its
formation before the closure of
the chorioidal fissure
•Primary vitreous appears at the
time of formation of the optic
cup, is a fibrillated secretion of
the retinal cells, and fills in the
vitreous space with a feltwork of
fine fibrils
•Primary cellular vitreous
formation
•Vascularization of primary
vitreous
•Its mixed ectodermal and
mesenchymal origin

9. Congenital
and
development
abnormalities
•Mittendorf dot
•Muscae
volitantes
•Persistent
hyloid system
•Vitreous cyst

11. Failure of secondary vitreous
•COLOBOMA
•Vitreous tracts ,Transvitrous channel

15. • wt-4g
• Vol-4cc (2/3vol of entire globe)
 approximately 99 % water
1 % solid
• 0.9% salts
• 0.08% protein
• 0.02% mucopolysaccharide

16. STRUCTURE
• The vitreous is the largest and simplest
connective tissuse present as a single piece in
the human body
• Divided in 3 parts
1. Hyaloid layer or membrane
2. Cortical vitreous
3. Medullary vitreous

18. HYALOID LAYER
ANTERIOR HYALOID MEMBRANE:
Anterior most surface layer or condensation of
the vitreous body.
Lies 1.5 mm anterior to ora serrata.
Attachments: with lens – Hyaloidacapsular ligament of
Wiegert.
With other structure: hyalociliary zonule – anterior
hyaloid membrane to ciliary processes.
Retrolental ligament- anterior hyaloid to lens.
Coronary ligament- anterior hyaloid to posterior 1/3rd of
ciliary processes circumferentially.
Median ligament- anterior hyaloid to pars plana.

19. Patellar fossa – cup shaped anterior depression which
accommodates the lens.
Berger’s space – separates vitreous body from lens.
POSTERIOR HYALOID MEMBRANE:
From vitreous base to optic cup.
Subhyaloid space: between internal limiting membrane
of retina and posterior hyaloid.

21. Peripheral zone of vitreous mass.
Constitute 2% of total vitreous.
0.2-0.3mm in width.
Condensed fibrillar gel form.
Made up of type 2 collagen fibrils inter with s
o
d
hyaluronate mps.
Metabolic centre of vitreous body.
Cortical vitreous cells:
Hyalocytes – 90%
Fibrocytes & glial cells – 10%

22. CENTRALVITREOUS
Forms major part of vitreous body.
Less fibrillar than cortical vitreous.
Cell free.
Homogenous but exhibit wavy lines.
Watered silk appearance in slit lamp .

23. Vitreous tracts
• Vitreous tracts are fine sheet like condensations of vitreous tissue which
radiate into the virteous space from ciliary body and ant retina
•

24. Topographic subdivisions of
vitreous space

25. VITREOUS BASE
At ora serrata.
Anterior extension: to adjoining
pars plana part of ciliary body
anterior to ora serrata.
Posterior extension: to peripheral
retina posterior to ora serrata.
Strongest attachment of vitreous.
Collagen fibres of cortical vitreous
are inserted at right angles at
base.

26. ATTACHMENTSOFVITREOUS(contd)
Optic disc (weak attachment).
Back of lens (by hyaloido capsular ligament o
f
Wiegert)
Para macular area (weak oval attachment).
Para vascular attachment.

28. BIOCHEMICAL COMPOSITION
• Composed of 3 major structural components
1. Water
2. Collagen-like fibres
3. Hyaluronic acid a glycosaminoglycans(GAGs)

29. TRANSPORT PROCESSES
• The active pump mechanisms located at level
of ciliary body ,pigment epithelium and
possible retinal vessels are concerned with
active transport of materials across the
vitreous

30. VITREOUS EXPANSION AND CONTRACTION
Its is a funtion of ionic charge of the vitreous
structure
POSITIVE CHARGE
Na
Nacl
Protien mol
NEGATIVE CHARGE
Hyaluronic acid
TEMP AND PH –cause shrinkage of vitreous
FREEZES –expansion of vitreous

31. THANK YOU