Comparison Of Two Approaches To Liquid Bubble Donor Preparation For Dmek

To evaluate the clinical implications of the liquid bubble (Szurman technique; LBT) and a partial liquid bubble (PLBT) DMEK preparation techniques.

Department of Ophthalmology, Medical University of Vienna

This study retrospectively compared the degree to which endothelial cells were preserved using the PLBT as compared to a LBT (Szurman technique) when performed by a single surgeon, sourced from a single eye bank. The LBT was performed as described in literature, performing a complete detachment of Descemet’s membrane by injecting trypan blue dye through a prepared tunnel while preventing reflux with a surgical pad, concluding with trephination in the desired diameter. The PLBT similarly uses the injection of fluid to detach Descemet's membrane, but does not lift the entire layer from the stroma. After trephination, the released graft is stained via trypan blue bath.

Endothelial cell density measured after the 3-month follow-up was 1805 and 1916 cells/mm² respectively, differing significantly (p= .012). However, a double-scroll graft formation could be achieved and maintained until implantation in 94% of partial bubble preparations and 50% of liquid bubble preparations. Preoperative visual acuity was comparable between preparation techniques at 0.4 logMAR as well as postoperatively, at an average of 0.1 logMAR.

Eliminating mechanical stress on DMEK grafts allows for a significantly higher degree of endothelial cell preservation. However, achieving the desired double-scroll graft formation was possible less often. It is still unclear which factors define the differences graft scrolling behavior observed between PLBT and LBT.