Clinical Results of Laser In Situ Keratomileusis Using Different Types of Excimer Laser: LaserScan LSX(R) versus OmniMed II(R)

Yoo, Chungkwon; Lee, Kang Seok; Kim, Hyo Myung

Abstract

PURPOSE: This study was retrospectively conducted to evaluate the clinical results of consecutive 167 myopic eyes of 117 patients undergoing laser in situ keratomileusis(LASIK) for myopia with either of the two excimer lasers, which differ in the method of laser delivery: flying spot scanning versus broad beam.
METHODS
According to the laser used, the treated eyes were divided into two groups: Group I, 84 eyes of 58 patients with LaserScan LSX(R)(Lasersight Inc., USA); Group II, 83 eyes of 59 patients with OmniMed II(R)(Summit, USA). Each patient had been followed up for more than 6 months after surgery. Only single procedure outcomes were included. Mean preoperative spherical equivalents(SE) were -5.67+/-1.79 D(range:-1.50~-9.75 D) in group I and -6.40+/-1.79 D(range:-3.50~-9.75 D) in group II.
RESULTS
At postoperative 6 months, mean uncorrected visual acuity increased to 0.94 in group I and 0.88 in group II. Uncorrected visual acuity of 20/40 or better occurred in 100% of group I and 96.4% of group II, and of 20/20 or better, in 57.2% and 48.2%, respectively. No eye in either group lost more than 1 line of best-corrected visual acuity. Mean SEs at postoperative 6 months were -0.28+/-0.50 D in group I and -0.55+/-0.60 D in group II(P<0.05). Manifest SEs were within +/-1.00 D in 97.6% of group I and 84.3% of group II, and +/-0.50 D in 73.8% and 60.2%, respectively. Intra- or postoperative complications were subconjunctival hemorrhage(4 eyes, group I; 5 eyes, group II), Sands of Sahara syndrome(7 eyes, group I; 5 eyes, group II), epithelial ingrowth(1 eye, group II only) and infectious keratitis(1 eye, group II only). No case had a central island or irregular astigmatism postoperatively.
CONCLUSIONS
Our study suggests that LASIK using the LaserScan LSX(R)excimer effectively reduces myopia compared with OmniMed II(R). However, its predictability decreased as the attempted correction increased. LASIK for myopia less than -10 D with the LaserScan LSX(R)provided satisfactory refractive results that compare well with other reports in the literature.