title: Clinical outcomes of wavefront-guided laser in situ keratomileusis to treat moderate-to-high astigmatism.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the refractive and visual outcomes of wavefront-guided laser in situ keratomileusis (LASIK) in eyes with myopic astigmatism and cylindrical component ≥2.0 diopter (D).
  
  
  METHODS
  In this retrospective study, 611 eyes that underwent LASIK for simple or compound myopic astigmatism were analyzed. Preoperative refractive cylinder ranged from -2.00 D to -6.00 D (mean -2.76±0.81 D), and the sphere was between 0.00 D and -9.75 D (mean -2.79±2.32 D). Predictability, visual outcomes, and vector analysis of changes in refractive astigmatism were evaluated.
  
  
  RESULTS
  At 3 months after LASIK, 83.8% of eyes had uncorrected distance visual acuity of 20/20 or better, 90.3% had manifest spherical equivalent within ±0.50 D, and 79.1% had residual refractive cylinder within ±0.50 D of intended correction. The mean correction ratio for refractive cylinder was 0.92±0.14, the mean error of angle was -0.45°±2.99°, and the mean error vector was 0.37±0.38 D. A statistically significant correlation was found between the error of magnitude (arithmetic difference in the magnitudes between surgically induced refractive correction and intended refractive correction) and the intended refractive correction (r=0.26, P<0.01).
  
  
  CONCLUSIONS
  Wavefront-guided LASIK for the correction of myopic astigmatism is safe, effective, and predictable.
authors.affiliation: University of California, San Francisco, CA, USA ; Optical Express, Glasgow, UK.
authors.forename: Steven C
authors.initials: SC
authors.lastname: Schallhorn
authors.affiliation: Optical Express, Glasgow, UK.
authors.forename: Jan A
authors.initials: JA
authors.lastname: Venter
authors.affiliation: Optical Express, Glasgow, UK.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Hannan
authors.affiliation: Optical Express, Glasgow, UK.
authors.forename: Keith A
authors.initials: KA
authors.lastname: Hettinger
keywords: Hartmann–Shack aberrometer; myopic astigmatism; wavefront-guided LASIK