eye bank for ophthalmology medical students

OPHTHALMOLOGY

1. Eye bank

2. Eye Bank is a non profit organization which deals with the collection, storage and distribution of the donor cornea for the purpose of corneal grafting, research and supply of eye tissues to other eye banks for ophthalmic purposes .

3. THREE TIER ORGANIZATION An integrated system involving a three-tier community eye banking pyramid based on the infrastructure and manpower at all levels The three tiers proposed were eye donation centres , eye bank and eye bank training centres

4. EDC - Eye Donation Centers affiliated to a registered eye bank (1) public and professional awareness about eye donation (2) co-ordinate with donor families and hospitals to motivate eye donation (3) to harvest corneal tissue and collect blood for serology (4) to ensure safe transportation of tissue to the parent eye bank.

5. Eye banks Middle tier comprise of a strong network of 45 Eye Banks(EB) These Eye Banks are closely linked with 2,000 Eye Donation Centers- EDC, each of which would cater to a population ranging from 50,000 to 100,000.

6. Provide a round-the-clock public response system over the telephone and conduct public awareness programs on eye donation. Co-ordinate with donor families and hospitals to motivate eye donation/Hospital Cornea Retrieval Programs – (HCRP) To harvest corneal tissue To process, preserve and evaluate the collected tissue To distribute tissue in an equitable manner for Keratoplasty To ensure safe transportation of tissue

7. EBTC - Eye banking training cente r The top tier comprises of 5 Eye banking training centers (EBTC) All of the eye bank functions plus training for all levels of personnel in eye banking and research.

8. Functions of an Eye Bank Promotion Registration Tissue Retrieval Tissue Processing Tissue Evaluation

9. Eye Bank Tissue Harvesting Tissue Distribution Tissue Evaluation Tissue Preservation Public Awareness Research

10. Contraindications Systemic: AIDS Rabies Active viral hepatitis Creutzfeldt-Jakob disease Reye’s syndrome Death from unknown causes Congenital Rubella Active septicemia Leukemia (blast form) Lymphoma/ lymphosarcoma

11. Ocular: Intrinsic eye diseases Retinoblastoma Active conjuctivitis,iritis,uveitis,vitritis,retinitis Congenital abnormalities ( keratoconus ) Central opacities,pterygium Prior refractive procedures (radial keratotomy)

12. How It Works ?

13. STEPS OF EYE DONATION Donor selection Tissue retriva l Corneal examination Tissue transportation Storage of corneal tissueDistribution

14. Preliminary preparations Obtain legal permission. Go through the donor’s medical records for any contraindications. Wash hands and be prepared with aseptic dressing. Identify the donor. Collection of postmortem blood:10ml Femoral vein Subclavian vein Heart Jugular vein

15. E nucleation

16. Corneo -scleral button excision

17. Serological testing HIV HBV HCV Syphilis

18. Storage of donor tissue

19. Moist chamber storage Whole globe in a sealed container 4 degree C Advantages Simple, minimum manipulation Disadvantage – time limit only 48 hours

20. M-K medium Described by Mc-Carey & Kauffman. Mixture of tissue culture medium and Dextran (5%,40,000 MW) Buffer Antibiotics:Penicillin,Gentamicin,Polymyxin Storage period- 96hrs.

21. K-Sol P urified chondroitin sulphate in tissue culture medium . Storage:7-10days in 4 C

22. Cornea storage Media Storage time (days) MK 4 K-SOL 7 CSM 7 DEXSOL 10 OPTISOL 14 PROCELL 14

23. Long term Organ Culture storage system ORGAN CULTURE METHOD Upto 35 days Earle’s salts without L- glutamine L- glutamine Decomplemented calf serum 1.5% chondroitin sulfate

24. MEM media(minimum essential media) Developed by Harry Eagle. 34 degree C Incubated at room temperature in nutrient medium Storage period : 30 days Advantage : Enables HLA matching

25. Very long time preservation CRYOPRESERVATION Corneal rim is passed through a series of solutions containing increasing concentration of dimethyl sulfoxide (DMSO) upto 7.5% Tissue frozen at controlled rate upto -80 deg C Stored indefinitely at -160 deg C Not popular Disadvantages Expensive Highly trained technical persons needed Slight error can lead to tissue damage

26. Assessment of Donor Tissue Slit lamp examination eyeball Corneal button by specular microscope

27. Corneal epithelium microcystic edema, epithelial defects Corneal stroma opacities, infiltrates, edema, DM folds Endothelium Guttata , snail track marks (stress fractures of endothelium) Anterior chamber – any crystals

28. Specular microscopy Edothelial cell density - < 1500cells/mm Severe polymegathism or pleomarphism Presence of cornea guttata Abnormally shaped endothelial cells – fused cells Abnormal single cell defects Severe edema of endothelium Presence of inflammatory cells on endothelium

29. GRADING OF TISSUE EXCELLENT No epithelial d efect No arcus senilis No folds in DM Excellent endothelium – no defects POOR Vacuolated cells Severe stromal cloudiness Marked folds Endothelium- marked defects, low cell density, central vacuolated cells

30. CORNEA GRADING - EXCELLENT - VERY GOOD - GOOD - FAIR - NSFS (NOT SUITABLE FOR SURGERY)

31. NSFS (Not Suitable For Surgery) For Training and Research

32. THANK YOU