Effect of Refractive and Topographic Astigmatic Axis on LASIK Correction of Myopic Astigmatism

Abstract

To evaluate whether agreement or disagreement between the axis of astigmatism as determined by refraction and corneal topography has any influence on the outcome of laser in situ keratomileusis (LASIK) correction of astigmatism. Charts of 122 consecutive eyes of 75 patients (46 women and 29 men) who underwent uncomplicated, primary LASIK for myopic astigmatism were reviewed. The series was divided into two groups--group 1, "agreement" (77 eyes) with a difference between refractive and topographic axis of astigmatism < or = 15 degrees, and group 2, "disagreement" (45 eyes) with a difference > 15 degrees. The mean difference in axis of astigmatism was 10 +/- 17.20 degrees (range: 0 degrees to 86 degrees), and 63.11% of eyes were within a 15 degrees difference. A significant negative correlation was found between the percentage of corrected astigmatism and the degree of disagreement. The percentage of corrected astigmatism differed significantly between the two groups (P=.002) with better results in group 1 (agreement). Disagreement between refractive and topographic astigmatic axis is common. Approximately one third of eyes with astigmatism have > 15 degrees disagreement. Disagreement between refractive and topographic determination of the astigmatic axis can be considered a prognostic factor for LASIK correction of myopic astigmatism.