PURPOSE: To evaluate and compare the visual and clinical outcomes of wavefront-guided laser in situ keratomileusis (LASIK) with the Alcon CustomCornea (Alcon Laboratories Inc, Fort Worth, Tex) and VISX CustomVue (VISX, Santa Clara, Calif) systems.METHODS: Ninety-three eyes of 56 patients (50 and 43 consecutive eyes on CustomCornea and CustomVue, respectively) were enrolled in a prospective multisurgeon clinical outcome study. Uncorrected visual acuity (UCVA), best spectaclecorrected visual acuity (BSCVA), and manifest refraction were measured at 1 day, 1 week, 1 month, and 3 months postoperatively. Early treatment diabetic retinopathy study (ETDRS) visual acuity and contrast sensitivity were measured at 1 month and 3 months, and wavefront mapping at 3 months.RESULTS: Preoperatively, the CustomCornea group had a mean sphere of -3.90 ? 1.62 diopters (D) (range -0.50 to -7.25 D), mean cylinder of +0.62 ? 0.39 D (range 0 to +1.50 D), and mean manifest spherical equivalent refraction of -3.59 ? 1.54 D. The CustomVue group had a sphere of -3.87 ? 1.45 D (range -1.75 to -6.75 D), cylinder of +0.49 ? 0.36 D (range 0 to +1.50 D), and manifest spherical equivalent refraction of -3.62 ? 1.46 D. At 3 months, 98% of the CustomCornea group and 95% of the CustomVue group were within ?0.50 D. Ninety -nine percent of eyes did not change >0.50 D (manifest spherical equivalent refraction) between 1 month and 3 months. CustomCornea eyes improved on contrast sensitivity testing and had a better profile than CustomVue for 20/15 Snellen and 20/12.5 ETDRS acuity. Both laser groups had a decrease in higher order aberrations with statistical significance for coma and spherical aberration in the CustomCornea group.CONCLUSION: Wavefront-guided LASIK with both systems is safe and effective. [J Refract Surg 2004;20:S636-S643]