PURPOSE: To compare the morphology of laser in situ keratomileusis (LASIK) flaps created by 2 femtosecond lasers. SETTING: Ophthalmic Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China. DESIGN: Comparative case series. METHODS: The RTVue optical coherence tomography (OCT) device was used to measure the morphology of LASIK flaps created with an Intralase FS60 (Group 1) or Femto LDV (Group 2) femtosecond laser 1 week postoperatively. Nominal flap thickness was 110 vim for both devices. RESULTS: Group 1 comprised 408 flaps and Group 2, 408 flaps. The mean central flap thickness was 109.34 mu m +/- 7.57 (SD) in Group 1 and 103.91 +/- 6.07 mu m in Group 2 (P<.001). The mean flap thickness in Group 2 (105.37 +/- 4.56 mu m) was significantly thinner than in Group 1 (110.29 +/- 6.95 mu m) (P<.001). Corneal flaps in the 2 groups were uniform and regular, showing an almost planar configuration. The 2 groups had similar predictability; the mean deviation in flap thickness was 6.59 mu m in Group 1 and 6.56 mu m in Group 2 (P=.877). The maximum deviation from the intended 110 mu m thickness of 18 measurements was 7.1 mu m in Group 1 and 7.6 mu m in Group 2. CONCLUSIONS: The flaps in Group 2 were thinner than in Group 1. The 2 groups had similar predictability and uniformity in flap creation. (C) 2013 ASCRS and ESCRS