Corneal densitometry patterns in Descemet membrane endothelial keratoplasty and Descemet stripping automated keratoplasty

Purpose To compare corneal densitometry in a consecutive series of 52 endothelial keratoplasties (DMEK/DSAEK) using a Scheimpflug-based device after six months of follow-up. Methods Corneal densitometry (CD) values of 102 eyes were divided into three main groups: 33 DMEKs, 19 DSAEKs, and 50 healthy eyes without previous ocular surgery. The CD values were then analyzed and compared between the groups. We measured three main layers in depth and four different concentric zones at 1, 3, and 6 months postoperatively. Results In the DMEK group, total CD significantly decreased from 38.02 +/- 10.21 grayscale units (GSU) to 31.13 +/- 9.25 GSU (P < 0.01) between the first and the sixth month postoperative. In the DSAEK group, we found significant changes only between the first and three months after surgery (from 42.62 +/- 9.31 GSU to 38.71 +/- 10.53 GSU (P < 0.01). Regarding the concentric zones, CD in the DMEK group significantly decreased in the central zone from 33.55 +/- 12.07 GSU to 30.63 +/- 10.15 GSU (P < 0.01) and significantly increased in the periphery from 30.63 +/- 10.15 GSU to 36.72 +/- 9.37 GSU, (P < 0.01). The DSAEK group showed no changes in the central zone (from 36.91 +/- 13.80 GSU to 36.14 +/- 11.47 GSU, P = 0.52) and CD significantly increased in the periphery (41.91 +/- 9.28 GSU, P < 0.01). Conclusion When comparing CD values in DMEK versus DSAEK, we found no differences by layers or at central-paracentral concentric zones, although CD differences in the peripheral zones were statistically significant. This finding may be attributed to the thicker graft at periphery with a delayed clearance and less anatomical interphase in DSAEK.