Comparison of swollen and dextran deswollen organ-cultured corneas for Descemet membrane dissection preparation: histological and ultrastructural findings.

PURPOSE: To compare the use of swollen tissue versus tissue deswollen by addition of dextran to the medium in the dissection of organ-cultured Descemet membrane (DM) with regard to preparation-related characteristics and ultrastructural findings to optimize transplantation in Descemet membrane endothelial keratoplasty (DMEK).

METHODS

DMs of 20 corneoscleral rims were separated using organ-cultured groups, one immersed in culture medium without dextran (group A) and the other in medium with added dextran for 24 hours (group B). The preparation details were noted. The difficulty of preparation was analyzed using a scoring system (0 = impossible, 10 = easy). By means of a micrometer, ultrathin sections of endothelial layer were obtained. Presence of any residual stroma, thickness of the DM, thickness of the endothelial cell layer, and the smoothness of the lamella were analyzed.

RESULTS

In both group A and group B, all 10 usable DMs were available. Mean preparation time was 6.5 ± 1.4 minutes in group A and 6.1 ± 0.9 minutes in group B (P = 0.399). The difficulty score was 7.9 ± 1.9 in group A and 8.0 ± 2.0 in group B (P = 0.726). The total mean thickness of the DM (without the endothelial cell layer) was 13.58 ± 2.81 μm in group A and 12.69 ± 2.06 μm in group B (P = 0.474). The total mean thickness of the endothelial cell layer was 3.99 ± 0.62 in group A and 3.98 ± 0.52 in group B (P = 0.989). Light microscopy and transmission electron microscopy revealed no evidence of any adherent remnants of corneal stroma on any specimen in each group.

CONCLUSIONS

DM-endothelium grafts for transplantation in DMEK procedures can be surgically prepared from organ-cultured corneal rims in swollen and deswollen conditions. Both separation methods seem to be equivalent in regard to the preparation characteristics of the obtained DM. Nevertheless, clinical studies are still necessary in order to confirm these findings.