Comparison of Manual and Femtosecond Laser–Assisted Descemet Membrane Endothelial Keratoplasty for Failed Penetrating Keratoplasty

Abstract

To compare outcomes of manual Descemet membrane endothelial keratoplasty (M-DMEK) and femtosecond laser-assisted Descemet membrane endothelial keratoplasty (F-DMEK) in treatment of penetrating keratoplasty (PK) graft failure. Setting: Retrospective, interventional comparative case series. PatientPopulation: Included were all patients with a failed PK graft who underwent either F-DMEK (10 eyes of 10 patients) or M-DMEK (29 eyes of 29 patients) at Toronto Western Hospital and the Kensington Eye Institute between 2014 and 2019, and had 6months of postoperative follow-up. OutcomeMeasures: Rates of graft detachment, rebubbling, rejection and failure, best spectacle-corrected visual acuity (BSCVA), and endothelial cell (EC) density. Rate of significant graft detachment (detachment requiring either rebubble or repeat keratoplasty) was 10.0% in F-DMEK and 65.5% in M-DMEK (P= .003). Rebubble rate was 10.0% in F-DMEK and 58.6% in M-DMEK (P= .011). Primary failure rate was 0% in F-DMEK and 27.6% in M-DMEK (P= .086). Rates of rejection and secondary failure did not differ between the groups (P= 1.000 for both). In a multivariable analysis, F-DMEK was found to be the only independent factor significantly associated with reduced postoperative detachment. Postoperative BSCVA at 6months returned to prefailure levels in both groups, with no significant difference between the groups at any time point. EC loss rates were 43.8% in F-DMEK and 38.0% in M-DMEK at 6months (P= .453). F-DMEK is a safe and effective procedure in failed PK patients, with outcomes comparable to M-DMEK, and with reduced detachment and rebubble rates. A trend towards reduced primary failure should be further studied.