AIM: To assess and compare the flap morphology using anterior segment optical coherence tomography (AS-OCT) in laser in situ keratomileusis(LASIK) with Femto LDV femtosecond lasers versus Hansatome mechanical Microkeratome. METHODS: AS-OCT (Visante) was used to compare 1 month postoperatively the morphology of the flaps created with Femto LDV femtosecond lasers or Hansatome Microkeratome. The intended ?ap thickness was 110μm and 160μm respectively. The thickness of twenty-five points across each flap, which were 0mm, 1.5mm, 2.5mm, and 3.5mm to the corneal vertex on the horizontal, vertical, 45° and 135° meridian respectively, was evaluated. RESULTS: One month postoperative, the central flap thickness in the Femto LDV group was 107.43±4.70μm, while 125.90±17.50μm in the Hansatome group. The difference between the actual and the expected ?ap thickness was 5.61±3.84μm and 31.52±12.27μm, respectively. The Hansatome group had presented a statistically signi?cant result (P﹤0.001). Flap morphology showed a more regular planar shape in the Femto LDV group and a meniscus shape in the Hansatome group. CONCLUSION: AS-OCT is a direct and fast procedure to assess the flap morphology. The morphology by AS-OCT showed that the flaps created with Femto LDV femtosecond laser were more accurate and regular than the flaps created with Hansatome microkeratome.