[Clinical studies on Q-factor guided LASIK for the correction of myopic astigmatism].

OBJECTIVE: To compare the results of the Q-factor guided LASIK with the conventional LASIK for the correction of myopic astigmatism. METHODS: Forty-three eyes underwent Q-factor guided LASIK and 41 eyes were received conventional LASIK. The patients were followed up for more than 3 months . Examinations included refraction, distance and near vision, noncontact tonometer, topography (provide Q value), aberrometer, ultrasonic pachymetry, contrast sensitivity function. RESULTS: At 3 months, 97.67% of Q-factor guided LASIK eyes attained UNCVA 1.0 or better and 97.56% eyes in the control group. The mean postoperative SE for Q-factor guided LASIK group was (-0.19 +/- 0.20) diopters (D) at 3 months and (- 0.17 +/- 0.17) diopters (D) in conventional LASIK group. The postoperative Q value of Q-factor guided LASIK was (0.50 +/- 0.28) and (0.82 +/- 0.40) in the conventional LASIK group, significant difference was noted between two groups. Both Q-factor guided LASIK and conventional LASIK significantly increased spherical aberration, the mean RMS of postoperative spherical aberration were (-0.265 +/- 0.156) microm, (-0.487 +/- 0.159) microm respectively, significant difference were noted between two groups at 3 months . Contrast sensitivity was reduced at 1 week and restored at 1 month postoperatively in Q-factor guided LASIK, while in conventional LASIK it was reduced at 1 week, 1 month and restored at 3 months. Corneal topography revealed in Q-factor guided LASIK the diameter of effective optical zone (EOZ) was (5.74 +/- 0.22) mm. However postoperative EOZ of conventional LASIK was (5.34 +/- 0.29) mm in control group. CONCLUSIONS: Q-factor guided LASIK is effective, safe and predictable for correction of myopic astigmatism. The postoperative visual quality of Q-factor guided LASIK is better than that of conventional LASIK due to its superiority for correction of spherical aberration.