Vitreous humour

Vitreous humour

1. Vitreous humour
PRESENTED BY
Nilesh kumar , Khushboo sahu,
Rukhmani sahu, Chanchal Sinha, Dimple Sinha,
B. Optometry 2
nd
Sem
ITM UNIVERSITY, NAYA RAIPUR, CG

2. VitrEous humour
DEFINITION

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. DIAGRAM OF VITREOUS HUMOUR

4. Structure Of Vitreous Humour

5. STRUCTURE
It may be divided into three parts
1. Hyaloid layer or membrane
2. Cortical vitreous
3. Medullary vitreous

6. 1. Hyaloid layer or membrane
•Outermost surface layer or condensation of
vitreous body
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

7. •Coronary ligament – anterior hyaloid to
posterior one-third of cilliary processes circum
ferentially
•Median ligament – anterior hyaloid to pars
plana
POSTERIOR HYALOID MEMBRANE /
POSTERIOR LIMITING MEMBRANE
•Extends back from vitreous based to optic disc
•Liesing contact with internal limitimg
membrane of retina

8. 2. Cortical vitreous
•Peripheral zone, approx 100μm in width vitreous
•Metabolic centre or vitreous body
•Cortical vitreous cells
Hyalocytes - 99%
Fibrocytes & glial cells - 10 %

9. 3. Medullary vitreous
•Forms major part of vitreous body
•Less fibrillar than cortical vitreous
•Homogenous but exhibit wavy lines
•Watered silk appearance in slit lamp

10. Vitreous tracts
•Sheets like condensation of vitreous tissue
radiating from ciliary body to retina
•Givens onions skin arrangement of adult
vitreuos
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

11. 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

13. 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

14. ATTACHMENTS OF VITREOUS
VITREOUS BASE
•At ora serrata
•Anterior extension : to adjoining pars plana
part of cilliary body anterior to ora serrata
•Posterior extension : to peripheral retina
posterior to ora serrata
•Strongest attachment of vitreous
•Collagen fibers of cortical vitreous are
inserted at right angles at base

15. ATTACHMENTS OF VITREOUS
•Optic disc (weak attachment )
•Back of lens ( by hyaloido capsular ligament of
wiegert)
•Para macular area (weak oval attachment)
•Para vascular attachment

16. Vitreous base & Posterior part of eye
ball

17. BIOCHEMICAL COMPOSITION
Water forms 99% of wet weight of
vitreous
All solids combined to form the remaining
1% of vitreous wet weight
MACROMOLECULAR CONSTITUENTS
COLLAGEN - The insoluble protein in vitreous
are present in form of fine fibres

18. HYAURONIC ACID
•It is mucopolysaccharide
•Macromolecules composed of equivalent
amounts of monosaccharides
•N – acetyl – glucosamine & glucuronic acid
SOLUBLE PROTEINS - soluble proteins
consentration of vitreous is very low & this
does not scatter light

19. Low molecular weight constituent
SUGAR
vitreous gel contains glucose, galactose,
manose, fructose, glucuronic acid and
glucosamine
ASCORBIC ACID
Concentration of ascorbic acid is higher in
vitreous than that of plasma
AMINO ACID
21 amino acid have been demonstrated in
vitreous humor of autopsied eyes

20. Physiochemical properties
Weight & volume
weight- 4g
volume - 4CC
OPTICAL PROPERTIES - high water content
combine to maintain the gel in high
state of transparency
•Refractive index of vitreous gel is 1.3349

21. PLASTICITY - Plasticity provided by 3 network
of randomly oriented rod like collagen
fibres

VISCOELASTICITY -
Viscoelasticity is provided by network of
hyaluronice acid molecular chains

22. REFRENCES
•A.k. khurana & Indu khurana