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BMJ Open Ophthalmol
BMJ Open Ophthalmol
bmjophth
bmjophth
BMJ Open Ophthalmology
2397-3269
BMJ Group BMA House, Tavistock Square, London, WC1H 9JR

37282692
bmjophth-2022-EEBA.3
10.1136/bmjophth-2022-EEBA.3
Oral abstracts
Theme 1 – COVID 19: Challenges for, or impact on, eye banking and corneal transplantation
1506
3 Emergency salvage of time expired clinical corneas during the COVID-19 pandemic
Hogg Penny
Joseph Agatha
Eagle Mark
Mason Ian
Rooney Paul
NHS Blood and Transplant, Liverpool, UK
2022
16 11 2022
7 Suppl 2 Abstracts of the European Eye Bank Association Virtual Meeting, 3–5 March 2022 A1A2
© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.
2022
https://creativecommons.org/licenses/by-nc/4.0/ This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/ .

Introduction

Corneas for clinical use can be stored for a maximum of 28 days in organ culture medium after death. At the beginning of the COVID-19 pandemic in 2020 it became apparent that; a rare situation was arising in that clinical operations were being cancelled and that there would be a surplus of “clinical grade” corneas. Consequently, when the corneas reached the end of the storage period, if the tissue had appropriate consent, they were transferred to the Research Tissue Bank (RTB). However, University research had also stopped due to the pandemic and there was a situation where the RTB had good quality tissue without any users. Rather than discarding the tissue, a decision was made to store the tissue for future use by cryopreservation.

Materials and Methods

An established protocol for cryopreserving heart valves was adapted. Individual corneas were placed into wax histology cassettes then inside a Hemofreeze heart valve cryopreservation bag with 100 ml cryopreservation medium (10% Dimethyl sulphoxide)). They were frozen in a controlled rate freezer (Planer, UK) to below -150oC and stored in vapour phase over liquid nitrogen (VPLN) below -190oC. To assess morphology, six corneas were cut in half, one half was processed for histology whilst the other half was cryopreserved, stored for 1 week then thawed and processed for histology. The stains used were Haematoxylin and Eosin (H&E) and Miller’s with Elastic Van Gieson (EVG).

Results

Comparative histological examination indicated that there were no visible, major, detrimental changes in morphology in the cryopreserved group as compared to the controls. Subsequently, a further, 144 corneas were cryopreserved. Samples were assessed for handling properties by eye bank technicians and ophthalmologists. The eye bank technicians felt that the corneas may be suitable for training purposes such a DSAEK or DMEK. The ophthalmologists said that they had no preference between the fresh or cryopreserved corneas, and both would be equally suitable for training purposes.

Conclusion

Time expired, organ-cultured corneas, can be successfully cryopreserved using an established protocol by adapting the storage container and conditions. These corneas are suitable for training purposes and may prevent discard of corneas in future.

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