Learning Curve in Descemet's Membrane Endothelial Keratoplasty: First Series of 135 Consecutive Cases

To evaluate the learning curve in Descemet's membrane endothelial keratoplasty (DMEK) in the management of corneal endothelial disorders.

Retrospective, nonrandomized, clinical study at a tertiary referral center.

We included 135 eyes of 118 patients with Fuchs' endothelial dystrophy.

In a first group of 135 consecutive eyes, a DMEK was performed. To determine the extent of a possible learning curve in DMEK surgery, the whole group was divided into 3 subgroups of 45 patients, to compare clinical outcomes at 1, 3, and 6 months.

Best-corrected visual acuity (BCVA), endothelial cell density (ECD), and intra- and postoperative complications.

Among the 3 groups clinical outcomes were similar, with 73% of cases achieving a BCVA of ≥20/25 (≥0.8) and an average ECD of 1747 ± 527 cells/mm², at 6 months. Graft detachment was the main complication and correlated with intraoperative vitreous pressure (P<0.01). The detachment rate declined with experience: In the first 45 cases, a complete or partial graft detachment occurred in 20%, in the second group in 13.3%, and in the third group in 4.4%. Other complications were relatively uncommon: Failure to unfold or position the graft during surgery (0.7%), intraocular hemorrhage (0.7%), primary graft failure (2.2%), air-bubble induced angle closure glaucoma (3%), remnant host Descemet's at the interface (5.9%), and cystoid macular edema (0.7%). Surgeries (partially) performed by an inexperienced surgeon showed a similar clinical outcome and complication rate.

The learning curve in DMEK did not correlate with clinical outcome (BCVA and ECD), but rather to the presence of a functional graft. However, the number of functional grafts (decline in graft detachment rate) increased with surgical experience.

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