A clinical study comparing the changes in higher-order aberrations following SBK and femtosecond laser LASIK with a customized Q-factor and Kappa adjustment

Objective To compare the changes in higher-order aberrations following microkeratome SBK (OUP-SBK) and femtosecond laser LASIK (FS-LASIK) with customized Q-factor and Kappa adjustment.Methods This was a retrospective clinically controlled study.Forty-three patients (86 eyes)were divided into two groups:one group (46 eyes of 23 cases) was treated with the Moria One Use-Plus SBK and the other group (40 eyes of 20 cases) with a VisuMax FS-LASIK.Both groups had customized Q-factor and Kappa adjustment during laser ablation.Higher-order aberrations were measured preoperatively and 1 month and 3 months postoperatively.An analysis of variance and independent t test were used to analyze the changes in higher-order aberrations after FS-LASIK and SBK.Results At the 1st and 3rd month postoperatively,there was an increase in all higher-order aberrations in both groups (F=14.935,6.498,P＜0.01).In the SBK group,spherical aberrations (C40) and 4th order aberrations (C42,C44) had increased on the 1st and 3rd months (F=8.326,3.202,6.195,P＜0.01).The C40 in the FS-LASIK group had increased on the 1st and 3rd months (F=9.045,P＜0.01).A comparison of the SBK and FS-LASIK groups showed there were no significant differences when higher-order aberration (t=0.26,0.88,P＞0.05) and changes (t=0.74,1.24,P＞0.05) were compared postoperatively at 1 and 3 months.There were significant differences in aberration C44 in the 1st month (t=3.08,P＜0.01) and C4-2 and C44 in the 3rd month (t=-2.34,2.78,P＜0.05).Conclusion With customized Q-factor and Kappa adjustment during laser ablation,higher-order aberrations increase with both mechanical microkeratome and VisuMax femtosecond flap creation.There is no significant difference in the total change in higher-order aberrations,but there is a difference in some single higher-order aberrations. Key words: Keratomileusis, sub-Bowman's ;  Femtosecond laser;  Keratomileusis,laser in situ ; Wavefront aberration