This document discusses the processing, evaluation, and preservation of donor corneas for transplantation. It describes how corneas must be processed in a sterile, laminar flow hood to prevent contamination. Evaluation involves examining the corneas grossly, under a slit lamp, and using a specular microscope to check endothelial cell density and quality. Corneas can be preserved for short term in a moist chamber, intermediate term in tissue culture media, and long term using organ culture or cryopreservation at very low temperatures. Proper processing, evaluation, and preservation are crucial to ensure the safety and viability of donated corneas.

1. PROCESSING AND
PRESERVATION
ARUNACHALAM L

2. OVERVIEW
• EYE BANK
• PROCESSING
• EVALUATION
• PRESERVATION

3. EYE BANK

4. PROCESSING
IT MUST BE PERFORMED IN
• A LAMINAR AIR FLOW HOOD WHICH MEETS ISO CLASS 5 STANDARDS
• IN AN ACCREDITED OPERATING ROOM
TISSUE MUST PROCESSED IN SUCH A WAY AS TO PREVENT CROSS
CONTAMINATION AND LABELLING

6. EVALUATION
THE ULTIMATE RESPONSIBILITY IS DETERMINING THE SUITABILITY OF THE TISSUE
FOR THE TRANSPLANTATION .
IT INVOLVES
1. GROSS EXAMINATION
2. SLIT LAMP EXAMINATION
3. SPECULAR EXAMINATION

7. GROSS EXAMINATION
• WHOLE GLOBE
EYE WITH EXCESSIVE STROMAL HYDRATION SHOULD BE DISCARDED
UNLESS SPECULAR MICROSCOPY CAN BE DONE FOR ENDOTHELIAL CELL COUNT
• CORNEOSCLERAL BUTTON
COLOUR OF THE TISSUE STORAGE MEDIA IS TO BE NOTED
FOREIGN BODY CONTAMINATION

8. SLIT LAMP BIO MICROSCOPY

10. SPECULAR EXAMINATION
• KONAN'S EYE BANK SPECULAR MICROSCOPE - HIGH QUALITY IMAGES OF THE DONOR
CORNEA.
• RAPID AND ACCURATE CELL COUNT, AS WELL AS OTHER PARAMETERS SUCH AS
POLYMEGATHISM AND PLEOMORPHISM.
• BUILT IN PACHYMETER TO MEASURE CORNEAL THICKNESS.
• DONOR CORNEAS MUST BE WARMED TO ROOM TEMPERATURE FOR AT LEAST 1 TO 2
HOURS BEFORE EVALUATION TO ELIMINATE ARTIFACTS THAT APPEAR IN THE
ENDOTHELIUM AT LOW TEMPERATURE.
• EXAMINATION CAN BE DONE EVEN WITH THE CORNEAS BEING KEPT INSIDE STORAGE
MEDIA, THUS MINIMIZING CHANCES OF CONTAMINATION.
• WARMING THE PRESERVED CORNEAS WILL NOT AFFECT THE ENDOTHELIAL VIABILITY.
• DONOR ENDOTHELIAL CELL DENSITY SHOULD BE GREATER THAN AT LEAST 1500
CELL/MM² TO ENSURE SUFFICIENT DENSITY FOR CORNEAL DETURGESCENCE.

12. PRESERVATION

13. EYE BANK - PRESERVATION MEDIA
• SHORT TERM (48HRS) - MOIST CHAMBER
• INTERMEDIATE TERM (4 DAYS)
• -MCCAREY - KAUFMAN MEDIUM - 4 DAYS
• K-SOL MEDIUM - 7 DAYS
• DEXSOL MEDIUM - 10 DAYS
• OPTISOL MEDIUM - 14 DAYS
• LONG TERM STORAGE - ORGAN CULTURE - 35 DAYS
• CRYOPRESERVATION - 1 YEAR

14. SHORT TERM STORAGE METHODS
MOIST CHAMBER STORAGE:
• STORAGE OF THE WHOLE GLOBE FOR SHORT PERIOD OF TIME AT 4 DEGREE
• IT IS A CLOSED CONTAINER WITH COTTON GAUZE MOISTENED WITH STERILE
SALINE
• CONTAINER IS NEVER COMPLETELY FILLED WITH LIQUID
• ADVANTAGES: 1.SIMPLICITY 2. NEEDS LITTLE EXPERTISE & MANIPULATION 3.
INEXPENSIVE
• DISADVANTAGES: 1.STORAGE TIME LIMITED TO 48 HRS. 2. ENDOTHELIUM
REMAINS IN CONTACT WITH AQUEOUS.

15. INTERMEDIATE TERM STORAGE METHODS
• TISSUE MEDIA PRESERVATION:
ADVANTAGES:
1.PROVIDES A CHEMICALLY DEFINED & STABLE ENVIRONMENT
2.HELPS SUPPORT & ENHANCES METABOLIC ACTIVITIES
3.REDUCES THE STROMAL SWELLING
4.KEEPS THE TISSUE UNDER STERILE CONDITION TILL USE
5.PROVIDES TIME FOR EB TO SEROLOGICALLY SCREEN THE DONOR FOR
COMMUNICABLE DISEASES

16. INGREDIENTS :
• 1.DEXTRAN
• 2.CHONDROITIN SULPHATE
• 3.ELECTROLYTES
• 4.PH BUFFER SYSTEM
• 5.ANTIBIOTICS
• 6.ESSENTIAL AMINO ACIDS
• 7.ANTIOXIDANTS, ATP PRECURSORS8.
INSULIN
• 9.EGF
• 10.ANTIPROTEASES &
ANTICOLLAGENASES

17. DEXTRAN
• KEEPS PRESERVED CORNEA THIN.
• INITIALLY 5% OF 5,00,000 MOL WT. DEXTRAN IS USED.
• IN NEWER MEDIA 1% OF 40000MOL.WT IS USED.
CHONDROITIN SULPHATE.
• IT IS AKIN TO NATURALLY OCCURRING GAG IN CORNEA.
• IT IS AVAILABLE FROM WHALE(TYPE A),WINE (TYPE B),SHARK(TYPE C).
• HIGH MOL.WT CHONDROITIN SULPHATE MAINTAINS DETUREGENCE WHERE AS
LOW MOL.WT HELPS RETAIN VIABILITY OF ENDOTHELIUM
• ALSO ACTS AS AN ANTIOXIDANT

18. MC CAREY KAUFMAN MEDIUM
• COMPONENTS
• TIC 199
• 5% DEXTRAN
• BICARBONATE BUFFER
• PENICILLIN AND STREPTOMYCIN WHICH WAS LATER SUBSTITUTED BY
GENTAMYCIN IN CON OF 50-200 MICRO GRAMS PER ML

19. MODIFIED MK MEDIUM
• WALTMAN AND PLAMBERG
• SUBSTITUTED 0.025 M HEPES BUFFER FOR BICARBONATE BUFFER
• PHENOL RED AS A PH INDICATOR.
• OSMOLARITY 290 MILLI OSM/KG
• PH 7.4
• STORAGE PERIOD 4 DAYS AT 4 DEGREE C.

20. LONG-TERM STORAGE
• 1. ORGAN-CULTURE METHOD
• 2. CRYO PRESERVATION

21. ORGAN CULTURE METHOD
• UP TO 35 DAYS
• CORNEOSCLERAL BUTTON IS PLACED IN PETRI DISHCONTAINING 15ML OF
MEDIUM.
COMPONENTS OF ORGAN CULTURE MEDIUM
• EAGLE'S MINIMUM ESSENTIAL MEDIUM
• EARLE'S SALTS WITHOUT L-GLUTAMINE
• L-GLUTAMINE DECOMPLEMENTED CALF SERUM
• 1.5% CHONDROITIN SULPHATE

22. CRYOPRESERVATION
• CAN BE PRESERVED FOR AN INDEFINITE PERIOD OF TIME
• DEVELOPED BY CAPELLA AND KAUFMAN
• CORNEOSCLERAL BUTTON IS PASSED THROUGH A SERIES OF SOLUTIONS
CONTAINING INCREASING CONCENTRATIONS OF DIMETHYL SULFOXIDE(DMSO)
UP TO 7.5%
• IT ACTS AS MEMBRANE STABILIZER FROZEN AT A CONTROLLED RATE UP TO -80
DEG C
• SUBSEQUENTLY STORED AT -180 DEG

23. ADVANTAGES
• EMERGENCY SITUATIONS LIKE CORNEAL TRAUMA AND PERFORATION
• FOR PERFORMING BACTERIOLOGICAL STUDIES ON DONOR TISSUE AND HLA
COMPATABILITY STUDIES
DISADVANTAGES
• NEEDS EXPENSIVE EQUIPMENT AND HIGHLY TRAINED PERSONS

24. THANK YOU
REMOVAL OF EYES
TAKES 20 MINS ONLY
DOES NOT DELAY
FUNERAL