Clinical Result of Excimer Laser Park

ABSTRACT

We evaluated the effectiveness of photoastigmatic refractive Keratectomy(PARK) by excimer laser on patients with compound myopic astigmatism. Spherocylindrical PARK was performed on 181 myopic eyes with astigmatism(mean spherical equivalent -6.61 D, range -1.88~-14.5 D) using the visx excimer laser. The eyes were divided into three groups according to the amount of desired astigmatic correction Group 1(-0.5~-1.0 D), Group 2(-1.25~3.0 D), and Group 3(-3.25~-5.5 D). Patients were followed up for 6 months. Uncorrected visual acuity at postoperative 6 month, was 0.80+/-0.27 in Group 1, 0.79+/-0.19 and 0.71+/-0.21bin Group 2 and 3 respectively. The mean spherical equivalent refraction was -0.24 D 6 months after PARK. Mean astigmatism was reduced from preoperative -0.85+/-0.51 D to postoperative -0.34+/-0.38 D in Group 1, from -2.08+/-0.65 D to -0.43+/-0.64 D and from -4.42+/-0.63 D to -1.23+/-1.25 D in Group 2 and 3 respectively. We also analyzed the angle of error, magnitude of error, index of success, and coefficient of afjustment by vector analysis. No significant complications were observed during the follow-up period. These results show that PARK by excimer laser was effective in correction of astigmatism. The effect of astigmatic correction in Group 2 and 3 were better than that of Group 1. Group 1 showed overcorrected tendency and Group 2 and 3 showed undercorrected tendency.