Comparison of Standard and Aberration-neutral Profiles for Myopic LASIK With the SCHWIND ESIRIS Platform

PURPOSE: To compare the induced corneal wavefront aberration of eyes treated for myopia by LASIK with the SCHWIND ESIRIS laser using an aspheric aberration-neutral (Aberration-Free (TM)) ablation profile versus a classical Munnerlyn standard profile. METHODS: Two consecutive groups of myopic eyes were analyzed. One group (70 eyes) was treated with a standard non-aspheric Munnerlyn profile (standard group, mean spherical equivalent refraction -4.09 +/- 1.77 diopters, [D] [range: -7.75 to -0.75 D] and mean cylinder 0.78 +/- 0.76 D [range: 0.00 to 3.00 D]), and the second group (70 eyes) was treated with the ORK-CAM aspheric aberration-neutral profile (aberration-neutral group, mean spherical equivalent refraction -3.71 +/- 1.80 D [range: -8.25 to -0.75 D] and mean cylinder 1.00 +/- 0.97 D [range: 0.00 to 4.50 D]). Visual outcome, corneal wavefront data, and topographic changes after 3-month follow-up were compared. RESULTS: Both groups had a good visual acuity outcome with refractive predictability of +/- 0.50 D in approximately 96% of the cohort. In terms of safety, one eye in the standard group lost two lines of Snellen visual acuity. In the aberration-neutral group, no eye lost. more than one line of Snellen visual acuity and 6% gained more than two lines. Corneal aberrations were measured up to the 7th order (36 Zernike terms). The induced postoperative corneal wavefront aberration at 4.0 and 6.0 mm was compared. At 6.0 mm, corneal coma increased after myopic LASIK by 0.09 mu m in the standard group and by 0.07 mu m in the aberration-neutral group. The induction of corneal spherical aberrations in the standard group was 0.17 mu m (0.22 D) versus 0.09 mu m (0.13 D) in the aberration-neutral group. The root-mean-square of induced higher order aberrations was 0.19 mu m in the standard group and 0.16 mu m in the aberration-neutral group. Topographies showed multi-focality of 0.50 D in the standard, group and 0.25 D in the aberration-neutral group. CONCLUSIONS: Both groups had good predictability and safety results. With the aspheric aberration-neutral profile, less corneal wavefront aberration was induced compared to eyes treated with the standard profile. [J Refract Surg. 2009;25:339-349.]