Learning curve and procedural standardization in liquid-bubble DMEK: impact on preparation efficiency, complication rates, and endothelial cell survival.

PURPOSE: Analyzing experience-related changes and procedural standardization in DMEK using liquid-bubble preparation technique.

METHODS: In this retrospective single-center study, 2929 eyes underwent DMEK between 2014 and 2024. The first and last 50 DMEK procedures for Fuchs endothelial corneal dystrophy performed by seven surgeons were compared (Block 1 vs. Block 2). Outcomes included surgical time, intraoperative complications, rebubbling, repeat DMEK, corrected distance visual acuity (CDVA), central corneal thickness (CCT), and endothelial cell density (ECD) up to 12 months.

RESULTS: Mean graft preparation time decreased by 30% (p = 0.013). Mean surgical duration decreased significantly over time in both isolated DMEK and Triple-DMEK procedures across all surgeons, with operative times reduced by 26.3% and 21.8%, respectively (all p ≤ 0.001). Preparation-related complications declined (33% vs. 18%; p < 0.01), as did intraoperative graft turning (22.9% vs. 10.6%; p < 0.001) and repeat DMEK rates (10.9% vs. 4.9%; p = 0.005). Rebubbling rates remained unchanged (32.9% vs. 30.3%; p = 0.63) but were associated with lower 12-month ECD (p < 0.001). Postoperative graft turning was also associated with reduced ECD (p = 0.02). Despite lower donor ECD in Block 2 (p < 0.001), 12-month ECD and endothelial cell loss did not differ between blocks.

CONCLUSIONS: Liquid-bubble DMEK was associated with improved efficiency and reduced complication rates over time. These temporal changes were observed during a period of increasing surgical experience and progressive procedural standardization. Long-term endothelial outcomes remained stable and largely independent of individual surgeons, while rebubbling and graft turning were the main determinants of endothelial cell loss.