Clinical comparison of 6 aberrometers Part 2: Statistical comparison in a test group

PURPOSE: To compare and mutually validate the measurements of 6 aberrometers: the Visual Function Analyzer (Tracey), the OPD-Scan (ARK-10000, Nidek), the Zywave (Bausch & Lomb), the WASCA (Carl Zeiss Meditec), the MultiSpot Hartmann-Shack device, and the Allegretto Wave Analyzer. SETTING: University Hospital Antwerp, Antwerp, Belgium. METHODS:This prospective study was conducted on a group of 44 healthy eyes with refractions ranging from -5.25 diopters (D) to + 5.25 D (cylinder 0 to -2 D). For each aberrometer and each eye, the averaged Zernike data were used to calculate various kinds of root-mean-square (RMS). These parameters, together with the refractive parameters, were then analyzed with a repeated-measures analysis of variance (ANOVA) test, complemented by paired t tests. A similar analysis was done for the comparison of the variances of these parameters. RESULTS: The aberrometers gave comparable values for all studied parameters with the following exceptions: The CIPD-Scan underestimated the polynomials describing 4- and 5-fold symmetries, and the Visual Function Analyzer slightly overestimated the astigmatism terms. The 3rd-order radial RMS value was different for each device, as well as the RMS in the central 2.0 mm zone. The WASCA presented the lowest variance. CONCLUSION: These results suggest that in healthy eyes, all aberrometers produced globally similar results but they may vary in some details.