Donor corneas for transplantation: a scanning electron microscopic study of the epithelium.
OBJECTIVE
Donor corneas are processed in eye banks and used for transplantation as a standard routine. The maximum time limit post-mortem for harvesting donor tissue varies greatly between eye banks. This study aimed to examine the corneal epithelium for structural changes post-mortem.


METHODS
A total of 51 corneas harvested between 14 and 163 hours post-mortem were examined using scanning electron and light microscopy.


RESULTS
Cell loss occurred through desquamation of flat superficial cells during the first days. In corneas with a post-mortem time of more than 2-3 days, large superficial cell sheets and deeper cells detached, starting centrally. Deep peripheral cells remained. The loss of the superficial cells revealed the 3-dimensional structure of the epithelium and the membrane characteristics of deeper cells.


CONCLUSIONS
The longer the time post-mortem, the greater the epithelial cell loss. However, a rim of peripheral cells remained, even after 7 days. The superficial cell layer showed signs of strong lateral attachment and broke up in a sheet-like fashion. The intercellular adhesion between deeper cells and adhesion between the basal cells and the basement membrane appeared to be weak post-mortem. The cell membrane structures of the remaining cells were surprisingly well retained. The clinical implication of the study is discussed.
Slettedal
Jon Klokk
JK
Center for Eye Research, Department of Ophthalmology, Ullevaal University Hospital, Oslo, Norway. jon.klokk.slettedal@gmail.com
Lyberg
Torstein
T
Ramstad
Hanne
H
Nicolaissen
Bjørn
B
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016039:Corneal Transplantation; D019573:Epithelium, Corneal / Q000648:ultrastructure*; D005125:Eye Banks; D005260:Female; D006801:Humans; D008297:Male; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D011180:Postmortem Changes; D013997:Time Factors; D014019:Tissue Donors