Repeatability and agreement of wavefront aberrations of a new hybrid topographer and aberrometer in healthy eyes

Abstract

Purpose: To assess repeatability and agreement of the Pentacam AXL Wave with that of the iTrace aberrometer.

Setting: Narayana Nethralaya, Bangalore, India.

Design: Prospective, cross-sectional study.

Methods: All eyes of patients underwent 3 sets of measurements at a single visit, using Pentacam AXL Wave and iTrace. Lower-order aberrations (LOAs), higher-order aberrations (HOAs), and coma and spherical aberrations (SAs) were analyzed. Repeatability was assessed using within-subject (Sw) SD, test-retest variability (TRT), Sw coefficient of variation (CoV), and intraclass correlation coefficient (ICC). The Bland-Altman analysis was used to assess 95% limits of agreement (LoA) and the correlation coefficient (r) to determine strength of relationship between measurements.

Results: 100 eyes of 100 patients underwent measurements. Pentacam AXL Wave had repeatability with an ICC for total ocular aberrations ranging from 0.84 for HOAs to 0.92 for LOAs and for corneal from 0.76 for HOAs to 0.86 for LOAs. The Sw, TRT, and CoV of all aberrations were significantly lower (better) than those of iTrace (P < .001). The mean differences between 2 devices were insignificant for the comparison of all parameters, except for spherical aberration (0.011 [0.002571 to 0.02008]; P = .01). Both devices showed excellent correlations for ocular aberrations (total HOAs [P = .12, LoA = -0.52 to 0.025; r = 0.89]; LOAs [P = .14, LoA = -2.71 to 2.61; r = 0.96]; coma [P = .27, LoA = -0.11 to 0.12; r = 0.89]; and SA [P = .01, LoA = -0.09 to 0.07; r = 0.97]).

Conclusions: The repeatability estimates for wavefront aberrations using Pentacam AXL Wave were significantly better than those using iTrace. Both devices showed excellent correlations for total ocular aberrations.