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Ali Fadlallah, Belkacem Amari, Jean-marc Legeais; Comparison of the Wavefront Refraction and Ocular Aberrations measured by the VISX Wavescan and the new Generation Hartman-Shack iDesign Aberrometer. Invest. Ophthalmol. Vis. Sci. 2014;55(13):4849.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate agreements in wavefront refraction and aberration (lower and higher order) measurements by two Hartmann-Shack wavefront-sensing devices: the VISX WaveScan and Abbott iDesign aberrometers.
Using the VISX WaveScan and iDesign aberrometers, wavefront refraction and ocular aberrations at a fixed optical zone of 6 mm were measured on 100 eyes of 50 patients. Repeatability of measurements was evaluated using the intra-class correlation coefficient with 3 consecutive measurements on each aberrometer. Using subjective manifest refraction (MR) as the standard, the spherical equivalent (SE), sphere, and cylinder were compared to values measured by WaveScan and iDesign. Astigmatism was evaluated using vector analysis.
The mean differences in SE, sphere, and cylinder between MR and WaveScan were -0.28 diopter (D), -0.13 D, and -0.31 D, respectively, and between MR and iDesign, -0.79 D, -0.61 D, and -0.36 D, respectively. The VISX WaveScan was found to be statistically well correlated with subjective manifest refraction in the areas of sphere, cylinder and axis. However, the iDesign was found to be significantly higher in spherical measurements when compared to both manifest refraction (P=. 001) and VISX WaveScan (P=. 003). Vector analysis revealed mean differences of -0.44 +0.19 x 11 degrees between MR and WaveScan and of -0.98 +0.27 x 13 between MR and iDesign. Mean absolute defocus for WaveScan and iDesign was 3.98±2.76 and 2.11±1.21 root- mean-square (RMS) μm, whereas astigmatism was 0.68±0.52 and 0.39±0.22 μm, respectively. Pearson correlation coefficients between the two aberrometers were: 0.94 for defocus (p=0.001), 0.44 for astigmatism (p=0.028), 0.22 for coma (p=0.027), 0.62 for trefoil (p=0.021), 0.63 for spherical aberration (p=0.271), 0.13 for secondary astigmatism (p=0.01), and 0.51 for quadrafoil (p=0.01). Intra-class correlation coefficient values for both aberrometers over different aberration orders showed excellent repeatability.
Significant differences were noted between the measurements taken by the wavescan and the iDesign. Spherical measurements with the iDesign were different compared to manifest refraction. The WaveScan and iDesign aberrometers display similar spherical aberration, but show significant discrepancies in lower order and higher order aberration values.
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