Evaluation of the comparability and repeatability of four wavefront aberrometers.

Purpose: To compare total ocular aberrations and corneal aberrations obtained with four different aberrometers and to determine the repeatability and inter-observer variability. Methods: In this prospective comparative study, 23 healthy subjects underwent bilateral examination with four aberrometers: the Irx3 (Imagine eyes; Hartmann-Shack), Keratron (Optikon; Hartmann-Shack), iTrace (Tracey technologies; Ray tracing) and OPD scan (Nidek; Automated retinoscopy). Six images per eye were obtained. Second-order, third-order and fourth-order spherical aberration were exported for 5.0 mm pupils. Results: Significant differences in measurements were found for several total ocular aberrations (defocus (2,0), astigmatism (2,2), trefoil (3,-3), trefoil (3,3) and spherical aberration (4,0)) and corneal aberrations (defocus (2,0) and astigmatism (2,2)). The Irx3 showed the highest repeatability in measuring total ocular aberrations, followed by the Keratron, OPD scan and the iTrace. The repeatability of the corneal aberrations was highest for the iTrace, followed by the Keratron and OPD scan. The OPD scan showed a lower inter-observer variability, compared to the Irx3, Keratron and iTrace. Conclusions: Total ocular and corneal aberrations are not comparable when measured with different aberrometers. Hartmann-Shack aberrometers showed the best repeatability for total ocular aberrations and iTrace for corneal aberrations. It would be worth-wile in the future to evaluate aberrometers in patients with more aberrant eyes.