Authors: Michael Marchand, Mona H. Dagher, Marie-Claude Robert
Author Disclosure Block: M. Marchand: None. M. H. Dagher: None. M. Robert: None.

Abstract Body:

Purpose: Posterior lamellar keratoplasty has become the standard of care for endothelial pathologies, such as Fuchs endothelial corneal dystrophy (FECD) and pseudophakic bullous keratopathy (PBK), leading to faster recovery, fewer complications, and better vision outcomes compared with traditional penetrating keratoplasty. Descemet membrane endothelial keratoplasty (DMEK), in which only the Descemet membrane and endothelium are transplanted, has the potential to further improve visual acuity outcomes and decrease rejection rates. However, DMEK is technically challenging, and difficulty with donor preparation, graft attachment, and primary graft failure has been described. The purpose of this study is to report and analyse the clinical outcomes and complications of the first eyes that underwent DMEK surgery in our university-based center.
Study Design: Retrospective observational case series.
Methods: Eighty-five eyes of 73 consecutive patients who underwent DMEK between March 2016 and July 2018 were included in this study. DMEKs (n=91) were performed by five surgeons and included all their first cases. Outcome measures examined included pre- and postoperative best corrected visual acuity (BCVA), endothelial cell count (ECC), central corneal thickness (CCT), intraocular pressure (IOP), and intraoperative and postoperative complications (rejection, graft detachment, rebubbling rate, graft failure, need for reoperation). This study was conducted in compliance with the Declaration of Helsinki and approved by the CHUM Research Ethics Committee.
Results: The median BCVA increased from 0.40 [mean 0.59±0.50] logMAR (Snellen equivalent, 20/50) before surgery to 0.14 [mean 0.30±0.47] logMAR (Snellen equivalent, 20/25^-) 6 months after DMEK (p=0.002). The change in CCT was -123±45μm (p < 0.001), and -124±43μm (p < 0.001) at 6 and 12 months after surgery. Using pre-stripped and stamped grafts with post-processing endothelial cell counts of 2764±256 cells/mm, the mean postoperative ECC was 1597±587 cells/mmat 6 months and 1446±388 cells/mmat 12 months. The median endothelial cell loss at 6 months after DMEK was 39.8%. Fourteen eyes (15.4%) had graft detachment involving more than one third of the graft and required rebubbling. The mean rebubbling time was 10±5 days after DMEK surgery. No episode of graft rejection was observed in our cohort. However, nineteen eyes (20.9%) had DMEK graft failure for which 6 eyes (6.5%) had repeat DMEK, 11 eyes (12.1%) had Descemet stripping automated endothelial keratoplasty (DSAEK), and 3 eyes (3.3%) had penetrating keratoplasty (PKP). The mean regraft time was 17±13 weeks.
Conclusions: Our data suggest that DMEK is a safe and effective procedure for endothelial pathologies, with excellent visual outcomes. The low rejection rate makes DMEK an attractive alternative to DSAEK and PKP.