The influence of pupil center shift on wavefront-guided laser in situ keratomileusis

Abstract

To evaluate the pupil center shift quantitatively after pupil dilation and to investigate its influence on the outcome of wavefront guided LASIK. Sixty-three eyes in 32 myopic patients with order RMS higher than 0.35 or were divided into groups A and B, and the Zyoptix LASIK was applied to the patients of both groups In group A, pupil center was used as the center of ablation, while in group B the ablation center was adjusted based on the pupil center shift. A (0.173 +/- 0.114) mm mean pupil center shift was observed in this study, with the maximum 0.51 mm. At 3 months after the operation, there was no significant difference in visual acuity and refraction power between the two groups. However, the reduction of coma was (0.025 +/- 0.137) microm and (0.097 +/- 0.118) microm in groups A and B respectively (t = 2.131, P = 0.037). The change in spherical aberration was significantly different between the two groups. Pupil center shift after dilation is common. Adjustment of ablation center based on the shift may improve the correction of coma.