Search

Purpose This study aims to investigate possible differences in clinical outcomes between precut and surgeon-cut grafts for Descemet membrane endothelial keratoplasty (DMEK). Methods 142 consecutive patients who underwent DMEK were included in the study. 44 patients received precut tissues, and 98 patients received surgeon-cut tissues. Precut grafts were allocated to the patient by the German Society for Tissue Transplantation if available. We compared the outcomes of both groups for changes in visual acuity, central corneal thickness, endothelial cell density, re-bubbling rate, and graft failure rate. Results Patients who received precut tissues experienced similar increase in visual acuity (median change 0.4 logMAR) and decrease of corneal swelling (median change 132 μm) compared with those who received surgeon-cut tissues (median VA change 0.3 logMAR, p = 0.55, CCT change 118 μm, p = 0.63). There was no statistical difference in endothelial cell density (1436 vs. 1569 cells/mm2, p = 0.37), re-bubbling (32% vs. 35%, p = 0.85), and graft failure rate (5% vs. 1%, p = 0.23). No primary graft failure occurred in the group of precut grafts. Conclusion Both methods lead to comparable results for visual acuity, corneal deswelling, endothelial cell density, and re-bubbling rate. A previously described higher graft failure rate for precut tissues could not be confirmed in our study. Thus, we do not see medical reasons against the use of precut tissues. There are several advantages of precut DMEK tissues over surgeon-cut tissues, especially the prevention of graft loss during preparation in the operating theater.

PURPOSE: To determine the feasibility, dissection accuracy, and endothelial viability of ultrathin endothelial lamellae harvested from organ-cultured corneas using a single-pass with an innovative motor-driven linear microkeratome system. METHODS: Forty-eight (n = 48) paired organ-cultured human corneas were randomly assigned to dissection (study eyes, n = 24) with fellow eyes serving as the control (fellow eyes, n = 24). After organ culture and deswelling in a medium containing 6% dextran, endothelial lamellae with a target thickness

Purpose: To investigate and compare the surface roughness and morphology of posterior stromal lenticules created with a femtosecond laser using various pulse energies to that obtained with a mechanical microkeratome. Methods: A 150 kHz femtosecond laser platform (IntraLase iFS; Abbott Medical Optics) was programmed to create an 8.5-mm-diameter posterior stromal lenticule in 12 human corneal tissues. Specimens were dissected using different pulse energies (1.00, 0.75, 0.65, and 0.50) and fixed 2 mu m spot separations. Three additional posterior corneal lenticules were prepared using a mechanical microkeratome (Moria Evolution 3; Moria). After the procedure, each corneal tissue was examined by atomic force microscopy (Autoprobe CP; Veeco). Results: Femtosecond laser-treated tissues revealed similar morphological features, however, with significant differences in surface roughness in relation to the energy pulse used for lamellar dissection (P < 0.001). The most regular stromal surface was achieved when using 0.50 mu J pulse energy; on the contrary, the roughest specimens were those dissected using 1.00 mu J pulse energy. No differences in surface roughness were measured between mechanically resected tissues and those treated using 0.50 mu J pulse energy (P > 0.05). Conclusions: Atomic force microscopy submicron analysis of femtosecond-dissected donor tissues provided quantitative demonstration of the relation between pulse energy and stromal surface roughness. Surface quality of posterior corneal lenticules, comparable with that provided by mechanical microkeratome, is significantly improved when setting pulse energy for lamellar dissection of 0.50-mu J and 2-mu m spot separations.