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ANATOMY_OF_CORNEA presentation dhir.pptx
- 1. ANATOMY OF CORNEA Presenter : Dr Ruchika Dhir (1st year resident) Moderator : Dr Mansi Chandna DHIR HOSPITAL AND POSTGRADUATE INSTITUTE OF OPHTHALMOLOGY
- 2. DIMENSIONS Normal Cornea Micro Cornea Megalo Cornea Neonates 10mm <9mm Adult 12mm < 10mm > 13mm
- 3. MICROSCOPIC ANATOMY • THINNEST-ENDOTHELIUM • THICKEST-STROMA
- 4. EPITHELIUM
- 5. BASAL LAMINA (BASEMENT MEMBRANE)
- 6. BOWMANS MEMBRANE • ACELLULAR • 8-14u • DOES NOT REGENERATE • COLLAGEN TYPE 1,3,5
- 8. DUA’S LAYER (PRE-DESCEMENTS LAYER) • ACELLULAR • TYPE 1 COLLAGEN • THICKNESS 15u • IMPERVIOUS TO AIR
- 9. DESCEMENTS MEMBRANE •THICKNESS 10-12u •RESISTANT •REGENERATES •BASAL LAMINA OF ENDOTHELIUM •TYPE 4 COLLAGEN
- 10. ENDOTHELIUM • THICKNESS 10u • HEXAGONAL IN SHAPE • DO NOT REGENERATE • PERIPHERY > CENTRAL
- 11. NERVE SUPPLY
- 12. TRANSPARENCY OF CORNEA • ANATOMICAL FACTORS
- 13. MAURICE THEORY • REGULARLY ARRANGED COLLAGEN FIBRILS IN STROMA • LESS DIA (275-300 A) • SEPARATED BY LESS THAN HALF THE WAVELENGTH OF LIGHT
- 14. TRANSPARENCY OF CORNEA • PHYSIOLOGICAL FACTORS :- IP = IOP - SP
- 15. ENDOTHELIAL PUMP
- 17. EMBRYOLOGY • 3 WAVES OF NCC MIGRATION BETWEEN LENS AND SURFACE ECTODERM •
- 18. REFERENCES • ANATOMY & PHYSIOLOGY OF EYE : AK KHURANA • AAO
- 19. • Thank you
- 20. DRUG PENETRATION • SOLUBILITY-BOTH LIPID AND WATER SOLUBLE
- 21. METABOLISM OF CORNEA METABOLISM GLUCOSE 3 PATHWAYS • HMP SHUNT • TCA CYCLE • GLYCOLYSIS
- 22. LIMBUS • 3 STRUCTURES • PALISADES OF VOGT • JUNCTION OF C-S STROMA • COLLECTOR CHANNEL
Editor's Notes
- HORIZONTAL DIAMETER-11-12 MM VERTICAL DIAMETER-9-11MM PERIPHERALLY LESS SPHERICAL AND MORE FLAT CENTRAL CORNEA MORE CURVED CENTRAL THICKNESS-500-600 MICRONS
- STRATIFIED NON KERATINISED SQUAMOUS EPITHELIUM 3 DIFFERENT TYPES OF EPITHELIAL CELLS BASAL CELLS ON BASEMENT MEMBRANE SINGLE LAYER OF COLUMNAR CELLS PROLIFERATING ABILITY RESTS ON Basement membrane ADHERED BY HEMIDESMOSOMES WING CELLS 2-3 LAYERS OF WING LIKE CELLS HAVE DESMOSOMES,ADHERENCE JUNCTIONS,GAP JUNCTIONS SUPERFICIAL CELLS TERMINALLY DIFFERENTIATED,FLAT ,POLYGONAL COVERED WITH MICROVILLI DO NOT PROLIFERATE GLYCOCALYX TO MAINTAIN TEAR FILM HAVE DESMOSOMES,TIGHT JUNCTIONS,ADHERENCE JUNCTIONS BASEMENT MEMBRANE COMPOSED MAINLY OF LAMININ AND COLLAGEN 4
- RCE=RECURRENT CORNEAL EROSIONS ATRAUMATIC TYPE-EBMD-DEFECTIVE HEMIDESMOSOMES
- KERATOCYTES PREDOMINANT CONEAL STROMAL CELLS FIBROBLAST LIKE PRODUCE BOTH COLLAGEN AND PROTEOGLYCANS COLLAGEN LAMALLAE PROPERLY ARRANGED COLLAGEN MOLECULES ASSEMLE INTO COLLAGEN FIBRILS THAT THEN ASSEMBLE INTO COLLAGEN FIBRES MAINLY TYPE 1 COLLAGEN PROTEOGLYCAN MATRIX=GROUND SUBSTANCE CORE PROTEINS AND GAG GAG ARE NEGATIVE CHARGED E.G.KERATAN SULPHATE DERMATAN SULPHATE CHONDRIOTIN SULPHATE DRAWS IN NA AND WATER
- MAURICE PROPOSED THAT CORNEAL TRANSPARENCY IS CONSEQUENCE OF A CRYSTALLINE LATTICE ARRANGEMENT OF COLLAGEN FIBRILS WITHIN STROMAL LAMELLAE AND THAT LIGHT SCATTERED BY INDIVIDUAL FIBRILS OF UNIFORM DIAMETER IS CANCELLED BY DESTRUCTIVE INTERFERENCE WITH SCATTERED LIGHT FROM ADJACENT FIBRE
- POST-PK CORNEA MICROCYSTIC EDEMA IOP VERY HIGH PTHISIS BULBI NOT COMPACT STROMA NO EPITHELIAL EDEMA