Effect of microkeratome suction duration on corneal flap thickness and incision angle

PURPOSE: To determine the effect of suction duration on corneal flap thickness and incision angle of the cut margin created by a microkeratome in a porcine eye. METHODS: Thirty porcine eyes were randomly assigned to three groups according to different suction duration: group 1 (10 sec), group 2 (35 sec), and group 3 (60 sec). The Hansatome microkeratome with a #160 plate and 8.5-mm-diameter suction ring was used to create a corneal flap with a diameter of 8.5 millimeters. Corneal flap thickness was measured by automated ultrasonic pachymetry, and the incision angle was assessed by measuring the angle of a sagittal section of the cornea using image analysis software. RESULTS: Mean corneal flap thickness in groups 1 (10 sec), 2 (35 sec), and 3 (60 sec) was 87.8 ± 22.0 μm, 116.0 ± 7.0 μm, and 127.2 ± 16.8 μm, respectively. There was a statistically significant difference between groups 1 (10 sec) and 2 (35 sec) (P=.005) and groups 1 and 3 (P=.004). The mean incision angle in groups 1, 2, and 3 was 34.8 ± 9.0°, 44.4 ± 16.1°, and 48.24 ± 15.3°, respectively. A statistically significant difference was found between groups 1 (10 sec) and 2 (35 sec) (P=.044) and groups 1 (10 sec) and 3 (60 sec) (P < .001). CONCLUSION: In laser in situ keratomileusis in porcine eyes, an increase in suction duration resulted in a thicker flap and greater incision angle.