Corneal Higher-Order Aberrations in Descemet Membrane Endothelial Keratoplasty versus Ultrathin DSAEK in the Descemet Endothelial Thickness Comparison Trial: A Randomized Clinical Trial

Abstract

Purpose: To compare corneal higher-order aberrations (HOA) after ultrathin Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK).

Design: Patient- and outcome-masked randomized controlled clinical trial.

Participants: Patients with damaged or diseased endothelium from Fuchs endothelial dystrophy or pseudophakic bullous keratopathy who were good candidates for DMEK or ultrathin DSAEK.

Methods: Corneal anterior and posterior surface HOA were measured with Scheimpflug imaging before surgery and at 3, 6, and 12 months after surgery. HOA after ultrathin DSAEK and DMEK were compared; correlation was performed between best spectacle-corrected visual acuity (BSCVA) and HOA at each time point.

Main outcome measures: Higher-order aberrations of the anterior and posterior cornea, expressed as the root mean square deviation from a best fit sphere reference surface.

Results: At 3, 6, and 12 months after surgery, the posterior corneal surface had significantly less coma (P ≤ 0.003) and total HOA (P ≤ 0.001) in DMEK compared with ultrathin DSAEK (4.0- and 6.0-mm OZ). Posterior trefoil (P ≤ 0.034), secondary astigmatism (P ≤ 0.042), and tetrafoil (P ≤ 0.045) were lower in DMEK than ultrathin DSAEK at 3, 6, or 12 months (either 4.0- or 6.0-mm OZ). There were no significant differences in anterior surface HOA between DMEK and ultrathin DSAEK at any post-surgical time. Compared with baseline, total posterior HOA was increased (P ≤ 0.036) in ultrathin DSAEK at 3, 6, and 12 months, in contrast to DMEK, where it was decreased (P ≤ 0.044) at 6 and 12 months (4.0- or 6.0-mm OZ, or both). At 6 and 12 months, posterior corneal total HOA correlated with BSCVA (ρ ≤ 0.635, P ≤ 0.001; 4.0- and 6.0-mm OZ). There were no moderate or strong correlations between anterior or combined corneal surface HOA at any time point after surgery.

Conclusions: Descemet membrane endothelial keratoplasty results in less posterior corneal HOA compared with ultrathin DSAEK. Descemet membrane endothelial keratoplasty decreases and ultrathin DSAEK increases posterior corneal HOA compared with presurgical values. Total posterior corneal HOA correlates with 6- and 12-month postoperative visual acuity and may account for the better visual acuity observed after DMEK.

Figure 1.

Baseline mean total higher-order aberration (HOA) (root-mean-square microns) of DMEK and UT-DSAEK groups by corneal surface at the 4.0-mm optical zone (A) and 6.0-mm optical zone (B). Total HOA = total higher-order aberration (Z_3-8); Error bars = 95% confidence interval.

Figure 2.

Mean total higher-order aberration (HOA) (root-mean-square microns) at the 4.0-mm optical zone of the anterior corneal surface (A) and the posterior corneal surface (B) at baseline, 3 months, 6 months, and 12 months after DMEK or UT-DSAEK. Total HOA = total higher-order aberration (Z_3-8). Error bars = 95% confidence interval. P indicates difference of group from baseline HOA.

Figure 3.

Mean total higher-order aberration (HOA) (root-mean-square microns) at the 6.0-mm optical zone of the anterior corneal surface (A) and the posterior corneal surface (B) at baseline, 3 months, 6 months, and 12 months after DMEK or UT-DSAEK. Total HOA = total higher-order aberration (Z_3-8). Error bars = 95% confidence interval. P indicates difference of group from baseline HOA.

Figure 4.

Correlation of ETDRS LogMAR best spectacle-corrected visual acuity (BSCVA) with posterior corneal total higher-order aberration (HOA) at the 4.0-mm optical zone 3 months (A), 6 months (B), and 12 months (C) after DMEK or UT-DSAEK. Total HOA = total higher-order aberration (Z_3-8). ρ = Spearman’s rho.