Endothelial cell loss following tissue harvesting by pneumodissection for endothelial keratoplasty: an ex vivo study.

Aims: To study ex vivo the difference in endothelial cell density (ECD) in tissue harvested by pneumodissection for pre-Descemet's endothelial keratoplasty (PDEK) and Descemet's membrane endothelial keratoplasty (DMEK).

Methods: Tissue for PDEK and DMEK were obtained from 10 eye bank sclerocorneal discs by trephination after air injection into corneal stroma and big bubble (BB) formation. PDEK tissue was prepared in five corneas after achieving a type 1 BB and DMEK after a type 2 BB in five corneas. Five sclerocorneal discs for each group were used as controls. Endothelial cell counts were obtained from all samples before and after injection using phase-contrast microscopy with an eyepiece reticle. We used paired t test to analyse the results using the GraphPad Prism V.6 software.

Results: The range of change of ECD before and after injection in the PDEK sample group varied from -9% to +0.2% with an average of -5.36% ±3.8%. The difference was not statistically significant (p=0.0512). On the other hand, the range of change of ECD of the DMEK groups before and after injection varied from -0.4 to -20.6, with an average of -12.44% ±8.11%. This difference was statistically significant (p=0.0456). Also, there was a significant difference between DMEK test samples (postinjection) and their controls (p=0.028).

Conclusions: Corneal endothelial cell loss in PDEK tissue preparation is no worse, if not slightly better than, in DMEK tissue prepared by pneumodissection. PDEK preparation by pneumodissection represents a viable graft preparation technique.