Contralateral assessment of sub-Bowman keratomileusis (SBK) microkeratome suction duration on laser-assisted in-situ keratomileusis (LASIK) flap characteristics

Purpose: to describe the effect of prolonging the standard suction duration during laser-assisted in-situ keratomileusis (lasik) and its effect on flap thickness and hinge length using sub-bowman keratomileusis (sbk) microkeratome. methods: fifty-six eyes (28 patients) were included and divided into 2 groups; group-a: eyes with flatter corneas (36 eyes,18 patients) and mean keratometric readings ranging from 40.13 to 43.71 diopters (d). group-b: eyes with steeper corneas (20 eyes,10 patients) with mean keratometric readings ranging from 43.85 to 46.72 d. one-use-plus sbk microkeratome was used for flap creation. for right eyes,flap was created immediately once suction was built up. in left eyes,the surgeon waited for 10 s after suction was built up before flap creation. flap hinge length and flap thickness were measured using surgical caliper and ultrasonic pachymetry,respectively. results: statistically significant differences were observed in corneal flap hinge size between right eyes versus left eyes,with a mean of 3.98 ± 0.48 vs. 3.78 ± 0.55 mm (p < 0.001). mean flap thickness in both eyes did not prove to be statistically significantly different with either surgical technique (90.2 ± 1.68 vs. 90.07 ± 1.44 μm,p = 0.8). sub-group analysis of group-a vs. group-b revealed hinge sizes that were significantly larger in steeper corneas (p < 0.01 and p < 0.05,respectively). however,flap thickness in both groups was unaffected by surgical procedure (p = 0.5). conclusions: increasing suction duration increases flap hinge length and stabilizes the flap,especially in steeper corneas. © 2016 iranian society of ophthalmology.