Reproducibility of LASIK flap thickness using the zeiss femtosecond laser measured postoperatively by optical coherence tomography.

PURPOSE

To evaluate LASIK flap reproducibility and uniformity created with a femtosecond laser using anterior segment optical coherence tomography (OCT).

METHODS

A prospective study of 87 consecutive eyes of 44 patients who had flaps created with the 200 kHz VisuMax femtosecond laser (Carl Zeiss Meditec) were included for flap thickness evaluation. All eyes were divided into two groups according to the intended flap thickness (110 μm or 120 μm) and the flap thickness was measured using anterior segment OCT (Visante, Carl Zeiss Meditec) at 1 week and 1 month postoperative. Flap thickness was measured at the flap center, 1.5-mm and 3.0-mm zone from the flap center, and along the 45° (including 225°) and 135° (including 315°) meridian (a total of 10 points).

RESULTS

The mean achieved flap thickness was 112.8±3.95 μm (range: 108.9 to 116.4 μm) and 112.3±3.84 μm (range: 109.6 to 115.1 μm) at 1 week and 1 month postoperative, respectively, in the 110 μm group, and 122.5±3.98 μm (range: 117.3 to 128.5 μm) and 122.2±3.93 μm (range: 115.8 to 129.0 μm), respectively, in the 120 μm group. The mean range of flap thickness at 1 month postoperative was 6.29±0.76 μm and 7.37±2.98 μm in the 110 and 120 μm groups, respectively.

CONCLUSIONS

Flap creation with the VisuMax femtosecond laser was found to be highly predictable with good reproducibility and uniform morphology when measured with anterior segment OCT.