The evolution of pre-descemet endothelial keratoplasty (PDEK)

Pre-Descemet's endothelial keratoplasty (PDEK) is an evolving endothelial keratoplasty (EK) procedure that merges the advantages of Descemet membrane endothelial keratoplasty (DMEK) and ultrathin EK methods. This review reports the latest anatomical, surgical, and clinical research on PDEK and discusses its potential future role in current EK practices. Anatomical data show that the Pre-Descemet/Dua's Layer (PDL/DL) acts as a biomechanical support, or "splint," for Descemet's Membrane (DM). This support facilitates the creation of grafts that are less tight and easier to handle compared to DMEK tissue. Notably, PDEK leads to rapid visual recovery and improvements in best-corrected visual acuity after surgery. Since PDEK results in an acceptable level of endothelial cell loss and has demonstrated reasonable detachment and rebubbling rates in published series, particularly in experienced hands, it is regarded as a reliable method for effectively utilising young and paediatric corneas, thereby optimising tissue use in eye bank procedures. Furthermore, advancements in surgical techniques, such as specialised PDEK clamps, an air-pump-assisted method, consistent 360-degree scoring, and the integration of optical coherence tomography into the surgical microscope, have resulted in higher success rates in creating Type 1 big-bubble, decreased overall tissue loss, and enhanced procedural consistency. Finally, PDEK merges the optical advantages of DMEK with enhanced intraoperative control and expanded donor options with the inclusion of young donor eyes, and is likely to gain wider adoption when integrated into training programs and eye bank protocols.