PURPOSE: To assess and compare the dimensions of laser in situ keratomileusis (LASIK) flaps created by the Intralase femtosecond laser (Intralase group) and the Ziemer FEMTO LDV femtosecond laser (Ziemer group) by Fourier-domain optical coherence tomography (OCT).
METHODS: RTVue OCT was used to measure the morphology of 816 LASIK flaps of 408 consecutive patients created with the Intralase (408 flaps) or the Ziemer (408 flaps) at one week postoperatively. Nominal flap thickness was 110μm for all patients and for both devices. Flap thickness was measured on 18 specified points on each flap to analyze the regularity, uniformity and accuracy of the two types of LASIK flaps.
RESULTS: The means of the central flap thickness made by Intralase group and Ziemer group were 109.34±7.57µm and 103.91±6.07µm（P<0.001）. The mean flap thickness in the Ziemer group (105.37±4.56µm) was significantly thinner than that in the Intralase group (110.29±6.95µm) (P<0.001). Corneal flaps both in the Intralase group and Ziemer group were uniform and regular, showing an almost-planar configuration. Intralase group and Ziemer group had similar predictability, and the average deviation of flap thickness was 6.59µm in the Intralase group and 6.56µm in the Ziemer group (P=0.877). The maximum deviation from the intended 110µm of 18 measurements was 8µm in the Intralase group, while the Ziemer group was 9µm.
CONCLUSIONS: The flaps made by Intralase femtosecond laser are thicker than those created by Ziemer femtosecond laser. Intralase group and Ziemer group had similar predictability and uniformity on flap creation. |
