The vitreous is a clear jelly-like structure that fills the vitreous cavity between the lens and retina. It is composed primarily of water along with collagen fibrils and hyaluronic acid which give it structure and elasticity. The vitreous develops in three stages - primary, secondary, and tertiary vitreous. It has three main regions - the hyaloid layer, cortical vitreous, and medullary vitreous. The vitreous provides optical clarity and acts as a scaffold that helps maintain the shape of the eyeball.

1. Vitreous

2. • Vitreous humour is an inert, transparent, jelly
–like, hydrophilic (dissolved in water) gel
structure
• Vitreous cpmposed of approximately 99%
water
• Vitreous cavity is bounded anteriorly by lens &
ciliary body & posteriorly by retina

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

4. Development of Vitreous

5. Formation of Primary VITREOUS
• 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

6. • Ingrowth of hyaloid artery through the embryonic
fissure. Ectoderm also contribute.
• Present in 1 st month of gestation.
• Regression of hyaloid artery by the end of 3 rd
month leads to retraction of primitive vitreous.
• Hyaloid artery is no longer patent and loses its
connection with disc- 7 th month.
• Remnants may remain as persistent pupillary
membrane.

7. FORMATION OF SECONDARY
VITREOUS:
• Sec avascular vitreous surrounds the primary
vitreous.
• Secreted by neuroectoderm of optic cup.
• Formation starts from 2 nd month and
completes by 5 th -6 th month.
• Marked by appearance of orderly array of fine
dense fibres.

8. FORMATION OF TERTIARY VITREOUS:
• Secreted by neuroectoderm in ciliary region.
• Secreted during 4 th month.
• Forms vitreous base & ciliary zonules.

11. 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

12. Hyaloid layer
• It is not a true membrane but outermost
surface of vitreous
1. Ant hyaloid membrane (ant limiting
membrane layer)
2. Post hyaloid membrane (post limiting
membrane layer)

13. ANTERIOR HYALOID MEMBRANE /
ANTERIOR LIMITING MEMBRANE
• Lies 1.5 mm anterior to oraserrata
• With other structure
• Hyalocilliary zonule- anterior hyloid membrane to
cilliary proccess
• Retrolental ligament – anterior hyaloid to lens
• Coronary ligament – anterior hyaloid to posterior
one-third of cilliary processes circum ferentially
• Median ligament – anterior hyaloid to pars plana

14. POSTERIOR HYALOID MEMBRANE /
POSTERIOR LIMITING MEMBRANE
• Extends back from vitreous based to optic disc
• Subhyaloid space: between internal limiting
membrane of retina and posterior hyaloid.

16. Cortical vitreous
• It lie in peripheral zone appox 100 micron in width
• It is more condensed fibrillar vitreous
• It contain Type 2 collagen fibrils interspersed with the
sodium hyaluronate ,mucopolysaccharide molecules
which provide viscosity ,elasticity and tensile strenght
to it
• 2 percent of the total vitreous vol
• It is the metabolic centre of the vitreous body(vitreous
cells –hyalocytes)
• Vitreos cells synthesize the hyaluronic acid

17. Medullary vitreous
• Similar to cortical vitreous except it is less
fibrillar structure and cell free
• Forms major part of vitreous body.
• Homogenous but exhibit wavy lines.
• Watered silk appearance in slit lamp.

18. Vitreous tract
• Sheets like condensation of vitreous tissue
radiating from ciliary body to retina
• Givens onions skin

19. Vitreous tracts seen in adult vitreous space are-
1.TRACTUS RETROLENTIS –
• Innermost tract attached anterior to posterior lens
capsule & posterior in front of optic disc
2. TRACTUS CORONARIUM
• Attached anterior to coronary ligament & posterior
lateral to tractus retrolentis
3 .TRACTUS MEDIANUS
• Attached anterior to ligament & posterior lateral to
tractus coronarium
4 . TRACTUS PRERETINALIS
• Attached anterior at ora serrata circum & posterior
lateral to tractus medianus

20. ZONES OF VITREOUS SPACE
• RETROLENTAL ZONE
– Anterior boundary – patellar fosa
• INTERMEDIATE ZONE
– Anterior boundry –epiciliary portion of anterior
hyaloid membrane
– Medially – tractus retrolentis
– Laterally – tractus preretinalis
– Coronary & median tract are present in this zone
• PRERETINAL ZONE
– Medially- tractus preretinalis
– Laterally - retina

22. BIOCHEMICAL COMPOSITION
• Composed of 3 major structural components
1. Water
2. Collagen-like fibres
3. Hyaluronic acid and glycosaminoglycans(GAGs)
• Macromolecules constituents are:
- Collagen: Type ii collagen :90%
Type ix collagen:10%
- Hyaluronic acid: N-acetyl glucosamine and glucoronic acid
- Soluble proteins: About 10% of serum conc. (low) And thus
does not scatter light

23. Vitreous expansion and contraction
• Vitreous has Na+ ions, NaCl and protein molecules
which neutralizes HA(hyaluronic acid)
→ expansion of vitreous
-vely charged HA molecules repel each other
Hyaluronic acid neutralization is disturbed
When Cationic molecules are removed(water)
Contraction of vitreous
If sodium ions /NaCl are replaced by
+ve protein molecules such as
protamine sulphate or cationic dyes

24. Physicochemical properties
Optical properties
• Transparency : Fine arrangement of vitreous
fibres and high water content
•Tyndall effect: Presence of low amount of
soluble proteins accounts for absence of light
scattering
• Light transmission: Transmits 90% of light
between 300-1400 nm

25. Plasticity: 3 D arrangement of collagen fibres
Viscoelasticity: Negatively charged hyaluronic
acid molecules precipitate extreme volume
changes with change in physicochemical
environment
Gel stability: collagen and hyaluronic acid interact
to stabilize the system termed as frictional
interaction
Molecular sieve effects: Selectively inhibit the
movement of water ,large molecules and cells

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