Wavefront-guided LASIK for Myopia: Effect on Visual Acuity, Contrast Sensitivity, and Higher Order Aberrations

PURPOSE: To determine the impact of wavefront-guided LASIK for myopia with or without astigmatism on high and low contrast best spectacle-corrected visual acuity (BSCVA), photopic and mesopic contrast sensitivity, and higher order aberrations. METHODS: Bilateral wavefront-guided LASIK (LADAR-Vision4000; Hansatome microkeratome) was performed on 324 eyes (162 patients) with a mean spherical manifest refraction of -2.84 +/- 1.35 diopters (D) (range: -0.25 to -6.50 D) and astigmatism of -0.81 +/- 0.74 D (range: 0 to -4.00 D). Mean age was 37.7 +/- 9.3 years (range: 20 to 60 years). Best spectacle-corrected visual acuity and contrast sensitivity were assessed using ETDRS charts and vertical sinusoidal gratings, respectively. Higher order aberrations were measured using a Shack-Hartmann wavefront sensor, analyzed across a 5-mm pupil. Repeated measures and post hoc analyses determined statistical significance (P<.0025). Only right eyes were analyzed. RESULTS: one hundred thirty-six eyes (84%) had uncorrected visual acuity of 20/20 or better 6 months postoperative; 80.9% (131 eyes) were within +/- 0.50 D attempted correction. Statistically significant postoperative improvements were noted in high and low contrast BSCVA (both P <=.001); in photopic contrast sensitivity at 3, 6, and 12 cycles per degree (cpd); and in mesopic contrast sensitivity at 12 and 18 cpd (all P<.001). With respect to higher order aberrations, a statistically significant change was seen in Zernike coefficients Z(3)(-1), Z(3)(1), Z(3)(-3), Z(3)(3), and Z(4)(4) following surgery (range of mean absolute change: 0.042 to 0.142 mu m; all P <=.001). All increased in magnitude except for Z(3)(-3), which decreased. CONCLUSIONS:Despite an increase in higher order aberrations, wavefront-guided LASIK yields excellent visual acuity and contrast sensitivity. Spherical aberration, which increases the most followlng non-Wavefront-guided LASIK, showed no significant change.[J Refract Surg. 2009;25:524-533.] doi:10.3928/1081597X-20090512-06