Comparison of Flap Characteristics Created with Two Different Methods in Laser in Situ Keratomileusis (LASIK)

BACKGROUND: The creation of corneal flap is considered to be the most critical part of laser in situ keratomileusis (LASIK) surgery. Currently, flaps can be created with mechanical micorkeratomes or femtosecond lasers. OBJECTIVE: To analyze and compare flap characteristics created with two different methods for flap creation in Laser in situ keratomileusis (LASIK). METHODS: This was a retrospective study. The thickness and morphology of the flap were compared between the two mechanical microkeratomes (group I – Moria M2, group II – Moria SBK One Use Plus) and femtosecond laser (group III – Ziemer Femto LDV). Central flap thickness was measured intraoperatively, while the flap profile was measured with anterior optical coherence tomography at two axes (90° and 180°) and 5 measuring points on the first day, the first week, and one month after the surgery. RESULTS: Central flap thickness was 110.91±15.79 micrometers (µm) (80-164 µm) in group I, 98.08±13.33 µm (65-136 µm) in group II and 103.52±13.89 µm (66-138 µm) in group III. Anterior optical coherence tomography revealed a meniscus-shaped flap in all three groups at both axes (90° and 180°). The least variability in flap thickness was observed in group III (±6 µm). CONCLUSION: All three methods of flap creation provide good shape and thickness reproducibility. Ziemer Femto LDV femtosecond laser had the least variable flap thickness in a single flap. Mechanical microkeratomes had slightly lower performance.