200 Hz flying-spot technology of the LaserSight LSX excimer laser in the treatment of myopic astigmatism - Six and 12 month outcomes of laser in situkeratomileusis and photorefractive keratectomy

Purpose: To evaluate safety, efficacy, predictability, and stability in the treatment of myopic astigmatism with laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) using the 200 Hz flying-spot technolo gy of the LaserSight LSX excimer laser. Setting: SynsLaser Clinic, Tromso, Norway. Methods. This retrospective study included 110 eyes treated with LASIK and 87 eyes treated with PRK that were available for evaluation at 6 and 12 mon ths, respectively. The mean preoperative spherical equivalent (SE) was -5.3 5 diopters (D) +/- 2.50 (SD) (range -1.13 to -11.88 D) in the LASIK eyes an d -4.72 +/- 2.82 D (range -1.00 to -15.50 D) in the PRK eyes. The treated c ylinder was 4.00 D in both groups. Eleven (8.5%) LASIK eyes and 8 (7.4%) PR K eyes had secondary surgical procedures before 6 and 12 months, respective ly, and were excluded when the 6 and 12 month outcomes were analyzed. Results: None of the eyes lost 2 or more lines of best spectacle-corrected visual acuity. Seventy-seven percent of the LASIK eyes and 78% of the PRK e yes achieved an uncorrected visual acuity of 20/20 or better; 98% in both g roups achieved 20/40 or better. The SE was within +/-0.5 D of the desired r efraction in 83% of the LASIK eyes and 77% of the PRK eyes; it was within /-1.0 D in 97% and 98%, respectively. The cylinder correction had a mean ma gnitude of error of 0.04 +/- 0.31 D (range -0.96 to +0.85 D) in the LASIK e yes and 0.02 +/- 0.37 D (range -1.44 to +0.72 D) in the PRK eyes, Refractiv e stability was achieved at 1 month and beyond in the LASIK eyes and at 3 m onths and beyond in the PRK eyes. Conclusion. The outcomes of this study are comparable to those achieved wit h lasers that use small-beam technology with a lower frequency, as well as with other types of delivery systems. They suggest that the 200 Hz technolo gy used in the LaserSight LSX excimer laser is safe, effective, and predict able and that with LASIK and PRK the results are stable when treating low t o moderate myopia and astigmatism up to 4.0 D. J Cataract Refract Surg 2001 ; 27:1263-1277 (C) 2001 ASCRS and ESCRS.