Zernike versus Fourier treatment tables for myopic patients having CustomVue wavefront laser in situ keratomileusis with the S4 excimer laser

Abstract

To compare the efficacy, predictability, and safety of Zernike-based versus Fourier-based treatment tables in myopic eyes 1 year after CustomVue wavefront laser in situ keratomileusis (LASIK) using the S4 excimer laser (Visx). Department of Ophthalmology, Stanford University School of Medicine, Stanford, California, USA. A prospective analysis of 32 eyes of 16 patients with myopia who had CustomVue LASIK with the S4 excimer laser was conducted using Zernike or Fourier treatment tables. Mean spherical equivalent (SE), uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and higher wavefront analyses were determined. The mean postoperative SE was -0.27 diopter (D) +/- 0.41 (SD) in Zernike-treated eyes and -0.20 +/- 0.29 D in Fourier-treated eyes. Twenty-eight of 32 eyes were available for analysis. Ninety-two percent of eyes in the Zernike group and all eyes in the Fourier group had 20/20 or better acuity (P = .85). Seventy-nine percent and 92%, respectively, were within +/-0.50 D of emmetropia (P = .68). All eyes in the Zernike group and 93% of eyes in the Fourier group had no change or gained at least 1 Snellen line of BSCVA (P = .85). Mean higher-order aberration values (mum) in the Zernike group and Fourier group were as follows: total root mean square, 0.91 and 0.99, (P = 0.95); defocus, 0.71 and 0.74, (P = 0.98); astigmatism, 0.15 and 0.31, (P = 0.81); coma, 0.21 and 0.20, (P = 0.99); trefoil, 0.11 and 0.11, (P = 1); and spherical aberration, 0.17 and 0.30, (P = 0.85), respectively. Myopic eyes that had CustomVue LASIK had better visual outcomes in the Fourier group than in the Zernike group. Higher-order wavefront aberration results were similar between the 2 groups.