Comparison of corneal flap morphology using AS-OCT in LASIK with the WaveLight FS200 femtosecond laser versus a mechanical microkeratome

Abstract

Purpose: To evaluate and compare the thickness and the morphology of femtosecond and mechanical microkeratome LASIK flaps using anterior segment optical coherence tomography (AS-OCT).

Methods: Bilateral LASIK was performed in 132 eyes from 61 myopic patients. Flaps were created in 72 eyes using the WaveLight FS200 femtosecond laser (Wave-Light GmbH, Erlangen, Germany) and in 50 eyes using the Moria microkeratome (Moria SA, Antony, France). AS-OCT was used 1 week postoperatively to evaluate the thickness of 17 points across each flap, which were 0, 2, and 3.5 mm to the corneal vertex on the horizontal, vertical, 45°, and 135° meridians.

Results: The mean central flap thickness was 105.53 ± 5.86 μm in the WaveLight group and 132.96 ± 13.91 μm in the Moria group (P < .001). The difference between the achieved and the intended flap thickness (accuracy) was 6.17 ± 3.98 and 23.60 ± 12.64 μm, respectively (P < .001). The standard deviation within individual flap (uniformity) was smaller in the WaveLight group. The symmetry and regularity were also better in the WaveLight group. Flap morphology showed a more regular planar shape in the WaveLight group and a meniscus shape in the Moria group.

Conclusions: AS-OCT showed that the flaps created by the WaveLight femtosecond laser were more accurate, reproducible, and uniform than those created by the Moria microkeratome.