Abstract
Purpose :
To analyze a 3- and 6-month secondary outcome of the DETECT randomized, controlled, double masked trial comparing Ultra-Thin Descemet Stripping Endothelial Keratoplasty (UT-DSAEK) to Descemet Membrane Endothelial Keratoplasty (DMEK): Higher-order aberrations from anterior, posterior, and combined corneal surfaces.
Methods :
At 3 months and 6 months post-operatively, patients with endothelial dysfunction from the DETECT trial underwent three-dimensional scans of the anterior segment with Scheimpflug imaging (Pentacam). Zernike vector values of the anterior, posterior, and combined corneal surfaces were calculated at 4.0- and 6.0-mm-diameter optical zones using the Pentacam software, based on relative height data between the cornea and a best-fit sphere reference surface. Root mean square deviations of individual aberrations (Coma, Trefoil, Spherical Aberration, Oblique Astigmatism, Tetrafoil) and total higher-order sum of Zernike orders 3-8 (Total HOA) were calculated for each group. Two-tailed Student’s t-test was used for statistical analysis.
Results :
216 patients were screened and 50 eyes of 38 patients were randomized to DMEK (25 eyes) or UT-DSAEK (25 eyes). At 3 months, the DMEK group had significantly less Coma (P≤0.018), Trefoil (P≤0.019), Oblique Astigmatism (P≤0.005), Tetrafoil (P≤0.005), and Total HOA (P<0.001) of the posterior corneal surface at both 4.0- and 6.0-mm-diameter optical zones. Similarly, at 6 months, the DMEK group had significantly less Coma (P≤0.003), Trefoil (P≤0.007), Oblique Astigmatism (P≤0.006), and Total HOA (P<0.001) of the posterior corneal surface at both 4.0- and 6.0-mm-diameter optical zones. At both 3 and 6 months, no significant differences in spherical aberration or HOAs of the anterior or combined corneal surfaces existed between groups.
Conclusions :
DMEK resulted in significantly less HOAs of the posterior corneal surface compared to UT-DSAEK. This may contribute to significantly better BSCVA in the DMEK group (manuscript submitted). However, corneal light-scattering, graft-host interface optical disparities, or differences in graft shape may also influence visual acuity. The loss of significant difference in tetrafoil from 3 to 6 months post-operatively may indicate that HOAs shift as grafts remodel over time. Longer term analyses of these factors with extended follow-up will better characterize the clinical outcomes of DMEK and UT-DSAEK.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.