In Vivo Endothelial Cell Density Decline in the Early Postoperative Phase After Descemet Membrane Endothelial Keratoplasty.

Purpose: To evaluate endothelial cell density (ECD) in the first 6 months after Descemet membrane endothelial keratoplasty (DMEK) by eliminating method error as a confounding variable.

Methods: From 24 DMEK eyes operated for Fuchs endothelial corneal dystrophy, from which specular microscopy images could be taken at 1 day and 6 months postoperatively, ECD values were compared between these 2 time points.

Results: Using the 1-day ECD measurement as baseline, mean ECD decreased from 1913 (±326) cells/mm to 1524 (±393) cells/mm at 6 months, a decline of -18 (±19)%. With the 1-week ECD as baseline [1658 (±395) cells/mm], the decline at 6 months was -6 (±19)% and when using preoperative ECD as baseline [2521 (±122) cells/mm], the decline was -39 (±16)% at 6 months.

Conclusions: After DMEK, ECD shows an in vivo decline of 18% from 1 day to 6 months postoperatively, with a sharp 13% drop in the first week, and a slower decrease thereafter. The remaining difference of 20% from preoperative ECD values may be attributed to a measurement error in the eye bank with an overestimation of the graft's viable endothelial cell population and/or intraoperative trauma to the graft.