Techniques for Graft Visualization and Identification of Graft Orientation: Endoilluminator-Assisted Descemet’s Membrane Endothelial Keratoplasty (E-DMEK) and Others

Descemet’s membrane endothelial keratoplasty (DMEK) [1] and pre-Descemet’s endothelial keratoplasty [2] (PDEK) are both techniques that utilize endothelial transplantation with either the Descemet’s membrane (DM) alone or by also including the pre-Descemet’s layer (PDL) [3]. As both these techniques utilize tissue transfer of grafts that are only 15–30 μm thick, there are certain challenges that are specific to both of these. Both these grafts always curl towards the side of the Descemet’s membrane as this structure is elastic in nature. This curling is crucial to identify as the graft needs to be positioned with the curls facing upwards in order to have the endothelial side facing downwards after graft floatation (Fig. 13.1). Difficulties that are often experienced by the surgeon relate to the transparency of the graft under the microscope light making it difficult to visualize the graft and to identify the orientation of the graft with relation to endothelial side. Various techniques have been used to try and identify the graft intraoperatively. The author (SJ) described the endoilluminator-assisted DMEK (E-DMEK [4] and the E-PDEK [5] techniques to enhance visualization in DMEK and PDEK, respectively.