Characterization of the Cleavage Plane in Descemet's Membrane Endothelial Keratoplasty

Abstract

To define the cleavage plane between Descemet's membrane (DM) and posterior corneal stroma in Descemet's membrane endothelial keratoplasty (DMEK) concerning its ultrastructural and immunohistochemical characteristics. Observational, consecutive case series. Fifteen corneoscleral buttons from donors 71.5±4.3 years of age stored in Optisol-GS and used for DMEK surgery in 15 consecutive patients. Endothelial cell-DM complexes (EDMs) and corresponding corneoscleral rims were investigated by transmission electron microscopy and immunohistochemistry using a panel of antibodies against adhesive matrix proteins. Ultrastructural and immunohistochemical characteristics of interface and cleavage plane between DM and posterior stroma. Connection between DM and corneal stroma was mediated predominantly by amorphous material of the interfacial matrix and projecting stromal collagen fibers. After DM stripping, the cleavage plane was located consistently between interfacial matrix and posterior stromal collagen lamellae, providing a largely smooth anterior EDM surface exposing the interfacial zone. Interindividual variations in amount and composition of the interfacial matrix resulted in variable degrees of EDM surface irregularities and variable staining patterns for adhesive matrix proteins such as fibronectin, vitronectin, amyloid P, osteonectin/secreted protein acidic and rich in cysteine (SPARC), fibulin-1, fibulin-2, fibulin-3, fibrillin-1, and keratoepithelin. The findings provide evidence for the existence of a physiologic cleavage plane between the interfacial matrix, the anteriormost adhesive zone of DM, and the corneal stroma, suggesting a relatively weak attachment that can be disconnected by mechanical forces. Interindividual variations in structure and composition of the interfacial matrix may provide an explanation for the variable attachment of EDM grafts to the recipients' corneal stroma and thus may affect the postoperative clinical outcome. The author(s) have no proprietary or commercial interest in any materials discussed in this article.