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

ABSTRACT

OBJECTIVE: To evaluate the pupil center shift quantitatively after pupil dilation and to investigate its influence on the outcome of wavefront guided LASIK. METHODS: 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. RESULTS: 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. CONCLUSIONS: Pupil center shift after dilation is common. Adjustment of ablation center based on the shift may improve the correction of coma.