Comparing the effect of three Descemet membrane endothelial keratoplasty injectors on endothelial damage of grafts

PURPOSE: Various injectors are commercially available for Descemet membrane endothelial keratoplasty (DMEK) but not all injectors have been studied for endothelial damage of grafts. The aim of the study was to compare endothelial damage in pre-stripped DMEK tissue from three clinically used injector devices: the modified Jones tube, the STAAR intraocular (IOL) injector, and the Geuder glass cannula in a laboratory setting. METHODS: Twenty-four human donor corneas were used for this study, eight for each study arm. Each endothelial graft was pre-stripped, trephined to 8.0 mm diameter, then loaded into either the modified Jones tube, the STAAR IOL injector, or the Geuder glass cannula by an eye bank technician who had no prior experience with any of the injectors. Grafts were then ejected, stained with Calcein acetoxymethyl (AM), and quantitatively analyzed using FIJI image software. The primary outcome was the percent of endothelial damage from injector loading and injection. Donor demographics were analyzed using Fisher’s exact test. The percentage of endothelial cell loss was compared across groups using the Kruskal–Wallis test. RESULTS: The mean percent of endothelial damage from after injection of the graft was 37.8% (±SD 12.2%) for the modified Jones tube, 37.0% (±SD 13.9%) for the STAAR IOL injector, and 23.5% (±SD 5.1%) for the Geuder cannula (P = 0.008). CONCLUSION: DMEK injectors contribute to intraoperative endothelial damage of transplanted grafts. The Geuder glass cannula may offer increased ease of use and less endothelial damage compared to the modified Jones tube or STAAR IOL injector for the novice user in early cases.