Comparison of the VISX WaveScan and NIDEK OPD-Scan Aberrometers

PURPOSE: To compare measurements obtained with the VISX WaveScan and NIDEK OPD-Scan (ARK 10000). METHODS: The VISX WaveScan is a wavefront aberrometer that uses Hartmann-Shack technology. The NIDEK OPD-Scan uses time-based retinoscopy (dynamic skiascopy). Measurements taken of 92 eyes from 51 patients using both aberrometers were retrieved and compared. Measurements included sphere, cylinder, axis, and Zernike coefficients of second to sixth radial order aberrations. The Zernike coefficients were normalized to a 6.0-mm pupil and used to calculate the root-mean-square (RMS) values of the radial orders, angular orders, total higher order aberrations, third order trefoil, third order coma, total spherical aberration, and total coma. Paired t tests were used to compare differences between measurements. RESULTS: Although no significant difference was found between the NIDEK OPD-Scan and subjective manifest refraction in sphere and axis, the NIDEK OPD-Scan measured significantly higher cylinder. No significant difference was found between the VISX WaveScan and subjective manifest refraction. The NIDEK OPD-Scan had significantly lower total higher order, second radial order, third order coma, total spherical aberration, total coma, and second angular order RMS values. The VISX WaveScan had significantly lower cylinder, trefoil, third-angular order, and fifth-angular order RMS values. CONCLUSIONS: Specific and significant differences were noted between the measurements taken by the VISX WaveScan and NIDEK OPD-Scan wavefront aberrometers.