Eye Banking and Corneal Transplantation

Eye Banking and Corneal Transplantation in New Zealand

Nigel Brookes

Technical Officer

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“The acquisition, evaluation & supply of high-quality corneal and other tissue to all New Zealanders needing a transplant to restore their sight”

• Overview of Service• History• Corneal Structure• Corneal Disorders• Corneal Transplant• Eye Banking• Eye Donation

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What Tissues?

• Amniotic membrane [30 - 50]– Structural/biological, surface

‘bandage’– Stored frozen (-80oC), up to 2

years

• Sclera [120 – 150]– Structural, reconstruction – Stored refrigerated, up to 1 year

• Corneas [300 - 350]– Viable, unaltered, sight-restoring– Stored in warm organ culture

(34OC), up to 28 days

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Transplant:CorneaSclera

Research:CorneaLensRetina

Medically unsuitable for transplant

Failed Eye Bank evaluation/testing

Amniotic membrane

Fresh donor eyes

Donor ‘rim’ after trephinationLimbal cells

Post-surgery:Cornea Defective tissue eg. keratoconic

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1905 First corneal transplant – Eduard Zirm, Czech.

1930 First whole eye storage

1944 First Eye Bank – New York

Up to 1970’s Moist pot whole globe storage

1988-1991 Cold storage in K-sol/ Optisol

1991 NZNEB started organ culture storage

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Cross-section Endothelial evaluation (in vivo)

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A: Superficial epithelium

B: Basal epithelium

C: Bowman’s layer with nerves

D: Bowman’s layer

E: Stroma with keratocytes

F: Endothelium

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• Since 1939, only 13 reports of disease transmission from

cornea: 9 rabies, 2 cancers, 2 Hep B

• Bacterial infection demonstrable but endophthalmitis after

corneal transplant similar to cataract surgery

• Cornea is highly inefficient transmitter of disease

• 3 reports of sCJD transmission: 1 now thought only possible

• No reports of transmission by sclera or amniotic membrane

Modern blood testing is highly sensitiveNAT testing further narrows ‘window period’

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• Donor acquisition from mainly Auckland area – within 24 hours• Links with donor sources: Mortuary, Hospitals, other transplant services• Donors selected by strict criteria for suitability• Long-term storage in 34oC culture system – up to 28 days• Extensive testing for infectious disease & contamination• Quality control / sterility of highest standard• Minimum endothelial cell count

• Supply 100% of all transplanted corneas in NZ

• Schedule of planned, elective surgery: 8+ grafts per week• Reduction of surgical waiting lists

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0

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19911992199319941995199619971998199920002001200220032004200520062007200820092010201120122013201420152016201720182019

Transplanted Not Transplanted

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• 8+ cornea bookings per week

• 23 corneal surgeons

• 16 centres

Public hospitals: 75 %

Private hospitals: 25 %

Scheduled: ~85%

Emergency: ~15%

AUCKLAND

Whangarei

Tauranga

New Plymouth

Hamilton

Wanganui

Hamilton

Wellington

Palmerston North

Dunedin

Christchurch

Nelson

Blenheim

Napier, Hastings

GisborneRotorua

Timaru

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A B C D

• Oldest form of transplant – 1905• 12.7 million people waiting for a corneal transplant• 185,000 transplants in 116 countries• Penetrating Keratoplasty most common form of transplant – USA 45,000 pa

UK 9,000NZ 350

Avascular – few rejection problems– no immunosuppression

12-18 months for optimal vision

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Corneal Transplant

Before After

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Keratoconus• Acquired abnormality – cornea protrudes, thin & distorted• Bilateral, progressive, occurs at young age (teens, twenties)• High prevalence in NZ – 50% of transplants• Does keratoconus progress more rapidly in NZ?

50%

Keratopathy/oedema• Painful epithelial blisters, scarring• Association with glaucoma & following cataract surgery

18%

Dystrophy• Intrinsic genetic disorders, or aging• Epithelial abrasion/erosion, endothelial cell loss & dysfunction 10%

Viral or bacterial infection• Inflammation – opacification – vascularisation - ulcers• Risk of rejection higher – blood vessels reduces graft tolerance 10%

Trauma• Perforation – physical/chemical injury• Heavy male preponderance 6%

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Dystrophy Bullous keratopathy

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MelanomaPterygium

Acid burn Perforated ulcer

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1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th

Age (decade)

Num

ber

Average: 47.5 years Trauma

RegraftViral keratitis

corneal oedema

KeratoconusMale: 52.4%Female: 42.9%

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• Full thickness of cornea replaced

• No host tissue remains

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• Leave host endothelium• Remove host anterior• Add donor anterior

minus endothelium

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• Leave host anterior• Remove host endothelium• Add isolated donor

endothelium

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• Centralise purchase cost of expensive equipment

• Quality checking prior to tissue use: endothelial density and quality.

• Technicians become proficient due to high volumes: consistent donor size, thickness.

• Surgeon and theatre time is saved: 30 mins approx.

• No cancellation of surgery when tissue ruined.

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Organs: heart, lungs, kidneys, liver, pancreas

• Only brain death - ICU• Specialist medical care of donor & family

Tissues: heart valves, skin

• Brain or circulatory death - autopsy• Repair defective heart valves, skin grafts

Eyes: corneas, sclera

• Brain or circulatory death• From any source: hospitals, Coronial, hospices, rest homes,

funeral directors, community

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Organ donation: heart, liver, kidneys, lungs, pancreas - ~100 per year

Tissue donation: skin, heart valves, bone - many 100’s per year

Eye donation: corneas, sclera - many 1000’s per year

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Age: 10 – 85 yearsTime: within 24 hours

Generally suitable:• Cancers• Heart disease, respiratory disease• Bacterial infection / septicaemia• Diabetes, arthritis• Vision problems or common eye disorders eg. cataract, glaucoma, retinopathy

Medical contraindications:• Death of unknown cause• Infectious disease: - Hepatitis B,C, HIV, meningitis• Systemic viral infection• CNS diseases, progressive dementia• Leukaemia, lymphoma• Previous corneal disease or surgery, laser surgery• Various congenital disorders• Lifestyle risk factors

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2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019

Australia Coroner Family Funeral Director Hospice Multi-organ

Multi-tissue Other Private Hospital Public Hospital USA

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13.6

36.1

30.1

11.7

8.5

0

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Ageexclusion

Timeexclusion

Medicalexclusion

Yes consent

No consent45

2

5

11

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3

81

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2019

Australia Coroner Funeral Director Hospice

Multi-organ Multi-tissue Public Hospital USA

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Suitable donors identified: by medical staff, transplant coordinatorsOR referral from families

Next-of kin contacted: - information provided about donation- possibility raised, no coercion- if consent given, process explained

Retrieval: - careful surgical procedure in hospital, mortuary, funeral home- donor treated with dignity & respect- no delay to funeral arrangements- no visible difference, viewing can occur

Driver’s licence is indication of wish only -important to discuss wishes with family/whanau

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• Acquisition after any death• 50 - 75% people suitable• Donation anywhere• Normal appearance • Plenty of time• No delay to funeral arrangements• Informed consent• Medical history interview – family, GP• Follow-up of outcome - memento

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• Donor characteristics• Technical & storage details• Serology/microbiology tests• Allocation & distribution

Eye Bank:

180

• Recipient details• Ophthalmic history• Surgical & graft procedure• Post-operative outcome

Recipient:45

Follow-Up: • Graft condition & survival• Visual acuity• Other ophthalmic procedures

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235

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NZNEB Trust10 ophthalmologists & 2 optometrists

Clinical DirectorDr David Pendergrast

Scientific DirectorProf Charles McGhee

ManagerLouise Moffatt

CoordinatorHelen Twohill

Technical OfficerNigel Brookes

Scientific AdvisorProf Trevor Sherwin

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The University of Auckland, Department of Ophthalmology and should not be reproduced without written permission.