Comparison of Thickness of LASIK Flap Created by Mechanical Microkeratome and Femtosecond Laser (Presented in Russian)
Narrative Responses:
Purpose
To evaluate thickness of laser in situ keratomileusis flap created by a mechanical microkeratome and a femtosecond laser using optical coherence tomography.
Methods
Prospective study included 52 eyes of 28 patients (10 men, 18 women) with a mean age of 31.3±8.3 years. Flap creation for LASIK was performed using the Nidek MK-2000 microkeratome (group 1) and the Zeimer Femto LDV Crystal Line femtosecond laser (group 2). There were 25 eyes in the group 1, 27 eyes in the group 2. The desired flap thickness was 130 µm in the group 1, 100 µm in the group 2. One day after surgery, flap thickness was determined at 18 points (9 points in horizontal and vertical meridians) by anterior segment OCT (Optopol SOCT Copernicus HR).
Results
Thickness of flap made with mechanic microkeratome was less than planned thickness (130 µm). In the horizontal meridian thickness of flap was 117.2±12.7 µm in the center, at the beginning of flap cut 122.7±16.2 µm, and at the end of cut 123.7±14.3 µm and near the flap hinge 112.5±11.9 µm. In vertical meridian thickness of flap was 130.4±16.3 and 125.6±15.0 µm on the periphery, 115.9±13.0 µm in the center. Flap thickness with femtosecond laser was 103.5±7.8 µm (with 100 µm planned).
Conclusion
Mechanical microkeratome forms a meniscus shape flap. The flap is maximally thin in center and thick on the periphery, however, it becomes thinner at the flap hinge. Femtosecond laser forms a corneal flap of uniform thickness throughout the whole flap, it maximally corresponds to the prognosed thickness.