Abstract
Purpose :
During DMEK graft processing, eye bank technicians occasionally encounter “flat” grafts that do not spontaneously scroll easily and are difficult to load without causing damage to the graft. In this eye bank laboratory-based study, we sought to determine if modification to the standard pre-loaded DMEK preparation technique resulted in additional damage or a characteristic pattern of damage to the graft after short-term storage.
Methods :
Six pairs of human donor corneas (age 65-80, with comparable cell counts and pre-processing damage) were prestripped, punched and loaded as a single scrolled graft by two experienced processing technicians. The OD graft was drawn into a Straiko modified Jones tube filled with Life4C using suction (standard loading procedure for our eye bank). The OS graft was picked up with forceps and dropped into a Life4C filled Straiko modified Jones tube. Grafts were stored in a Life4C filled Krolman viewing chamber for 24 hours at 4°C and then ejected onto a bed of calcein AM-supplemented viscoelastic, imaged with a fluorescent light microscope and analyzed for endothelial cell loss by FIJI segmentation. Mean endothelial cell loss was determined for standard loading and drop-in loading grafts and statistical significance determined using an unpaired Student’s t-test.
Results :
There was no difference in endothelial cell counts as determined by specular microscopy prior to graft processing (standard loading grafts, 2728.4 ± 333.8 cells/mm2; drop-in loading grafts, 2635.6 ± 369.2 cells/mm2, P = 0.6877). Mean ECL for standard loading protocol grafts was 21.4% ± 4.8%; mean ECL for drop-in loading grafts was 18.9% ± 4.6%, P = 0.4310. There was no consistent pattern of damage noted in DMEK grafts that underwent either standard loading or drop-in loading.
Conclusions :
Modification to the standard technique of preloading DMEK grafts by grasping the stripped, punched graft and dropping it into a storage media filled Straiko modified Jones tube does not result in additional damage to a DMEK graft as measured by vital dye staining, nor does it result in a characteristic pattern of cell death. This technique may be useful with flat DMEK grafts that are difficult to load without excessive contact with the edge of the Straiko modified Jones tube.
This is a 2021 ARVO Annual Meeting abstract.