Agreement of Corneal Aberrometry Between a New Pyramid Wavefront Aberrometer and a Scheimpflug-Based System

Abstract Purpose: To compare corneal aberrometry between Pentacam HR, a Scheimpflug-based imaging system, and Peramis, an aberrometer that combines a pyramidal wavefront sensor with Placido-disk topography. Methods: Bilateral eyes of 111 healthy participants were included. Corneal aberration terms—including total aberrations (TAs), lower-order aberrations (LOAs), higher-order aberrations (HOAs), trefoil (\(\:{C}₃±\:3\)), coma (\(\:{C}₃±\:1\)), and spherical (\(\:{C}₄⁰\)) aberrations—were recorded. The agreement between the systems was assessed using Bland-Altman analysis and two types of intraclass correlation coefficients (ICC): ICC-Abs for absolute agreement and ICC-Cs for consistency. Additionally, the mean measurements were compared. Results: TAs and LOAs demonstrated moderate to good agreement (ICC-Abs and ICC-Cs = 0.66–0.81). Similarly, Coma aberrations showed moderate agreement (ICC-Abs = 0.41–0.64, ICC-Cs = 0.44–0.64). In contrast, HOAs, trefoil, and spherical aberrations showed poor agreement (ICC-Abs ≤ 0.48, ICC-Cs ≤ 0.52). Except for HOAs (P-values = 0.08 and 0.06), there were significant differences between the systems for all aberration terms (P-values < 0.05). Differences were medium for TAs, LOAs, horizontal coma, and spherical aberrations (Hedges = 0.31–0.48) and mostly negligible otherwise. Limits of agreement (LoA) ranges were 1.67 to 2.33 D (diopters) for TAs, 1.68 to 2.33 D for LOAs, 0.61 to 0.69 D for HOAs, 0.76 to 0.86 D for trefoil, 0.70 to 0.82 D for coma, and 0.31 to 0.43 D for spherical aberrations. Conclusions: The Inter-device agreement was moderate to good for TAs, LOAs, and coma aberrations, and poor for HOAs, trefoil, and spherical aberrations. Therefore, these systems should not be used interchangeably for refractive surgery planning or follow-up.