Download MBBS Ophthalmology PPT 3 Eye Banking Lecture Notes

Download MBBS (Bachelor of Medicine, Bachelor of Surgery) Ophthalmology PPT 3 Eye Banking Lecture Notes


EYE BANKING

Department of Ophthalmology

Learning Objectives

At the end of the class, students shall be able to

? Understand the importance and need of eye banking
? Have basic knowledge of structure and functions of

eye banks

? Understand the various surgical procedures for
corneal transplantation
History

? 1903: E. Zirm(Czechoslovakia) performed 1st

successful human corneal transplantation.

? 1935: V P Filatov (Russia): Father of

keratoplasty and modern eye banking.

? 1944: Dr. R. Townley Paton established the first

eye bank in New York City.

? 1945: The first eye bank in India was started in

Regional Institute of Ophthalmology, Chennai.

? 1960 : 1st successful corneal transplantation in
India by Dr. Dhanda (Indore).
? 1974: McKarey and Kaufman developed M-
K medium which allowed the excised
corneo-scleral rim to be preserved for
up to 4 days at 4?C.
? 1985: Kaufman et al. presented K-Sol as a
storage method viable for up to 10 days.
? 1989: Eye Bank Association of India was formed.


WhydowenedanEyeBank?



Infectious keratititis



Injuries

? Open globe injuries
? Chemical injuries

Can be devastating
Need early intervention




What is an Eye Bank ?
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.

Structure of Eye Bank

? Medical section : Medical Director ( A qualified

Corneal Surgeon), Trained technicians

? Administrative Section: Eye Donation Counsellor /

Social Worker / Health Educator / Clerk
Functions of the Administrative Section

The administrative section is responsible for

- Public awareness programmes

- Liaison with government, local voluntary and

other health care agencies

- Fund raising

Functions of the Medical Section

Medical section deals with the entire technical

operation of the eye bank:

-Tissue harvesting, evaluation, preservation and

distribution

(maintaining medical quality of highest standard).


Functions of the Eye Bank

Networking of eye banks under the umbrella of a national

organisation ( e.g. Eye Bank Association of India) allows
-Public education programmes
- Institution of newer eye banking procedures
- Training programmes and

development of uniform medical standards

Eye Banking System
Eye Banking System

Eye Donation Center (EDC)
? 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.

Eye Bank (EB)
? 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 col ected tissue
? To distribute tissue in an equitable manner for Keratoplasty
? To ensure safe transportation of tissue
Eye Bank Training Centre (EBTC)
? Al of the eye bank functions plus training for al levels of personnel in

eye banking and research.


Equipments

EQUIPMENTS

EBTC

EB

EDC

Slit lamp

Required

Required

Not required

Refrigerators

Required

Required

Preferable

Serology

Required

Required

Not required

Specular

Required

Required if

Not required

microscope

col ection is

200/yr

Instruments for

Required

Required

Required

corneal excision

Autoclave

Required

Required

Should have

access

Laminar flow

Required

Required

Required

hood

How It Works ?

Recovery or

retrieval

Cornea

Processing

Distribution




Deceased family cal s Eye Bank

Grief counselor motivates

and obtains consent

Retrieval/ Recovery of

tissue
Tissue Retrieval

? Contraindications:

Systemic:

Ocular:

? AIDS

? Intrinsic eye diseases

? Rabies

? Retinoblastoma

? Active viral hepatitis

? Active

? Creutzfeldt-Jakob disease

conjuctivitis,iritis,uveitis,

? SSPE

vitritis,retinitis

? Reye's syndrome

? Congenital abnormalities

? Death from unknown causes

(keratoconus)

? Congenital Rubel a

? Central

? Active septicemia

opacities,pterygium

? Leukemia (blast form)

? Prior refractive

? Lymphoma/lymphosarcoma

procedures (radial

keratotomy)

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


Enucleation

Corneo-scleral button excision


Serological testing

? HIV

? HBV

? HCV

? Syphilis

Evaluation of donor tissue

? Gross examination
? Whole globe: eyes 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 to rule out contamination.


Evaluation of donor tissue

? Slit Lamp Biomicroscopic examination

Endothelial cell count

AGE

Average

Endothelial cell

count

10-19

2,900-3,500

20-29

2,600-3,400

Critical cell density:

30-39

2,400-3,200

300-500 cells/mm2

40-49

2,300-3,100

Functional cell density:

50-59

2,100-2,900

1500-2200 cells/mm2

60-69

2,000-2,800

70-79

1,800-2,600

80-89

1,500-2,300

* Philips C, Laing R, Yee R. Specular Microscopy. In: Krachmer JH, Mannis MJ, Hol and EJ (eds). Cornea,

2nd ed. Philadelphia: Elsevier Mosby, 2005:261-77.
Exclusion Criteria for penetrating keratoplasty*

? Cell density less than 2000 cells per square millimeter.

(Corneas with cell density less than 2000 cells / sq. mm

may be suitable for lamellar procedures).

? Extreme polymegathism or pleomorphism.
? Presence of significant guttata.
? Presence of many non-hexagonal or abnormally shaped

cells.

? Presence of inflammatory cells, bacteria, or debris on

endothelial surface.

? Numerous vacuolated cells.

*Standards of Eye banking in India 2009;NPCB;Director General of Health & Family Welfare, Govt. of India

Storage of donor tissue

Storage

Short term

Intermediate

Long term

2-3days

Very long term

7-10days

30days

Moist chamber

Organ culture

1year

(24hrs)

K-sol,

medium,

Cryopreservation

M-K medium

Dexsol,Optisol,

MEM

Optisol GS


Preservation of cornea

? Moist chamber storage
? Storage of whole globe
? 4C
? 24 hours
? Advantage: Simple
? Disadvantage:
Corneal stromal edema.


Preservation of cornea

? Tissue Media

Cornea storage Storage time

o Dextran

Media

(days)

o Chondroitin sulphate

MK

4

o Electrolytes

o pH buffer system

K-SOL

7

o Antibiotics

CSM

7

o Essential amino acids

o Antioxidants,ATP precursors

DEXSOL

10

o Insulin

OPTISOL

14

o Epidermal growth factor

PROCELL

14

o Antiprotease,anticoagulants
M-K medium:
? Described by Mc-Carey & Kauffman.
? Mixture of tissue culture medium (TC-199) and Dextran

(5%,40,000 MW)

? Buffer: HEPES (N hydroxyethyl- piperazine-N-ethane

Sulphonic acid)

? Antibiotics:Penicillin,Gentamicin,Polymyxin
? Storage period- 96hrs.
K-Sol:
? Purified chondroitin sulphate in tissue culture medium

(TC 199).

? Storage:7-10days in 40 C.

Preservation of cornea

? Long term Organ Culture storage system
? 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

? Very long time preservation:
? Cryopreservation
? 1year
CORNEAL TRANSPLANTATION

Cornea as transplant

? Immune privilege of cornea
? Absence of blood and lymphatic channel in the graft and

its bed

? Absence of MHC class I APCs in the graft
? Reduced expression of MHC coded alloantigen on graft

cells

? Immunosupressive microenvironment of aqueous humor.
? Anterior chamber associated immune deviation.
Corneal Transplantation

? Corneal transplantation refers to surgical replacement of a

full-thickness or lamellar portion of the host cornea with
that of a donor eye.

? Allograft/autograft

? Full-thickness( Penetrating)/ Partial thickness ( lamellar)

Corneal Transplantation :Schematic
Types of Keratoplasty

? Optical ? to improve vision

? Tectonic- to restore or preserve corneal integrity

? Therapeutic- to remove infected corneal tissue

? Cosmetic- to improve appearance

Keratoplasty : Schematic Diagram
Indications of Penetrating Keratoplasty(

PK)

? Keratoconus

? Post- cataract surgery edema

? Corneal dystrophies and degenerations

? Mechanical or chemical trauma

? Microbial/postmicrobial keratitis

? Congenital opacity

Lamellar keratoplasty

? Lamellar keratoplasty refers to replacement of only a portion

of the corneal layers of the host cornea with the graft.

? Indications:

-Opacification of superficial corneal stroma

-Marginal thinning or infiltration
-Localised thinning / descemetocele formation
Types of Lamellar Keratoplasty

? Superficial/ Deep anterior lamellar keratoplasty
( SALK/DALK)
? Descemet stripping automated endothelial

keratoplasty (DSAEK)

? Descemet membrane endothelial keratoplasty

(DMEK)

LEGAL ASPECTS IN INDIA

? Under the Transplantation of Human Organs Act, 1994

(THOA)

1. The qualification of doctors permitted to perform

enucleation (surgical eye removal) has been reduced

from MS (Ophth.) to MBBS.

2. Eye donation in India is always decided by the

donor's surviving relatives and not by the actual

donor.

3. Enucleating doctors always have to legally obtain a

written consent from the relatives of the deceased

before they actually remove the eyes.

This post was last modified on 07 April 2022