Comparison of higher-order wavefront aberrations with 3 aberrometers

PURPOSE: To evaluate the agreement of higher-order aberrations (HOAs) between aberrometers based on the Hartmann-Shack wavefront technology. SETTING: Department of Ophthalmology, Tri-Service General Hospital, Taipei, Taiwan. METHODS: Three clinical aberrometers WaveScan (Visx Inc.), LADARWave (Alcon Inc.), and Zywave (Bausch & Lomb Inc.) were used to measure HOAs in 34 cycloplegic eyes in 17 subjects. All the measurements in each subject were performed in I visit to reduce the impact of biologic fluctuation of HOAs. Each device was operated by an independent experienced operator, and the operators were blind to the data obtained from the other aberrometers. Root mean square (RMS) of coma, spherical aberration, and total 3rd- and 4th-order HOAs were compared between any 2 devices by a paired t test. RESULTS: WaveScan had the lowest mean RMS, whereas Zywave reported the highest mean RMS for any HOAs. The coefficients of variation were similar between any 2 devices. Paired t tests of RMS yielded a P value <.01 in 9 of 12 comparisons. In general, the largest discrepancies of HOA measures were between WaveScan and Zywave, and similar data were found between LADARWave and WaveScan. More than 80% of the absolute difference of HOA RMS between LADARWave and WaveScan, 50% to 78% between LADARWave and Zywave, and 38% to 59% between WaveScan and Zywave were within +/- 0.1 mu m. CONCLUSIONS: Significant discrepancies in HOA measurements were found among the 3 popular aberrometers. The HOA RMS data were closer between LADARWave and WaveScan, and HOA RMS by Zywave was generally higher than the other 2 devices. The 3 devices had comparable measurement variation.