A morphological comparison between sub-bowman keratomileusis flap and femtosecond laser-assisted flap in LASIK surgery for myopia

Abstract

Abstract Purpose: Comparison between the SBK microkeratome versus femtosecond laser in flap creation during LASIK surgery for myopia. Materials and Methods: This is a prospective comparative nonrandomized interventional clinical study that included 60 eyes of 30 patients in each group. Patients were randomized to receive either the SBK microkeratome or femtosecond laser technique according to a randomization computer software. The patient’s ages ranged from 18 to 46 years in the FS200 laser group and from 20 to 44 years in the SBK group. The WaveLight FS200 femtosecond laser and the Moria SBK microkeratome were both used to generate flaps in the 60 eyes of 30 patients (Moria SA, Antony, France). About 1 month after surgery, AS-OCT was utilized to measure the thickness of five locations on each flap that was 0, 1.5 mm from the corneal vertex on the horizontal and vertical axes. Hinge size and flap diameter were measured using a caliper 1 month after surgery. Uncorrected visual acuity and best corrected visual acuity were measured at 1 day, 1 week, and 1 month postoperative in each group. Any related complications were recorded in each group. For side-cut angles, scans were done across the temporal side of the flap, and then images were transferred to Draw editor software, and measurements were recorded and analyzed 1 month after surgery using AS-OCT. Results: The mean obtained central corneal flap thickness in both eyes in the FS200 laser group was 117.4 µ ± 4.18 SD, and 84.90 µ ± 3.74 SD in the SBK group, which was statistically significant (P < 0.05). The mean achieved Hinge size in both eyes in the FS200 laser group was 3.47 ± 0.26 mm, and 4.81 ± 0.63 mm (P < 0.05) in the Moria SBK group. The mean achieved flap diameter in the FS200 laser group was 7.95 ± 0.43 mm, and 9.15 ± 0.21 mm in the SBK group (P < 0.05). In the FS200 laser group, the average side cut angle was 126.93°9.56°, while in the SBK group, it was 37.18°6.93° (P < 0.05). Conclusion: In the two study groups, there was a statistically significant difference in the side cut angles that were intended and actually achieved. In comparison to the SBK group, the FS200 laser group had better predictability of flap thickness. There were reported complications in the SBK group, while femtosecond laser technology has shown better postoperative flap uniformity with no reported complications.