Comparison of corneal aberrations after microkeratome and femtosecond laser sub-Bowman's keratomileusis with a customized Q-factor

Abstract

Objective To compare the changes in aberrations following microkeratome sub-Bowman's keratomileusis (SBK) (OUP-SBK) and femtosecond laser SBK (Femto-SBK) with customized Q-factor. Methods This was a retrospective clinically controlled study. One hundred thirty-eight patients (276 eyes) were divided into two groups: one group (77 cases) was treated with Moria One-Plus SBK and the other group (61 cases) was treated with femtosecond laser SBK. The former group was divided into subgroups with spherical equivalents that included low myopia (17 cases) (≤-3.00 D) , moderate myopia (29 cases) (>-3.00 D, -3.00 D, <-6.00 D) and high myopia (24 cases) (≥-6.00 D). Both groups had customized Q-factors. Total higher order aberrations (HOA) , spherical aberrations (C40) , horizontal coma (C31) , vertical coma (C3-1) , horizontal trefoil (C33) and oblique trefoil (C3-3) were measured preoperatively and 1 month, 3 months and 6 months after surgery. Data were analyzed using repeated measured ANOVA, an independent samples t test. Results After surgery for the low myopia group, total corneal HOA, C40 and C3-1 were increased compared to preoperation (F=32.4, 14.6, 4.6, P<0.01) ; for the moderate myopia group, the total corneal HOA, C40, C31, C3-1, C33 was increased compared to preoperation (F=40.9, 22.5, 34.0, 2.7, 24.4, P<0.05) ; for high myopia, the total corneal HOA, C40, C31 and C3-1 were better for Femto-SBK than for OUP-SBK (F=15.4, 3.9, 10.4, 4.8, P<0.05). Conclusion For patients with high myopia, the increase in the degree of aberrations after Femto-SBK is smaller than that after OUP-SBK. Femto-SBK can provide patients with better visual quality. Key words: Wavefront aberration; Keratomileusis, laser in situ; Femotosecond laser; Keratomileusis, sub-Bowman's; Microkeratome