Comparison of corneal aberrations after biaxial microincision and microcoaxial cataract surgeries: a prospective study.

PURPOSE To compare the effects of biaxial microincision cataract surgery (B-MICS) and microcoaxial cataract surgery (C-MICS) techniques on corneal optical quality. MATERIALS AND METHODS In this prospective study, 40 eyes underwent B-MICS and 40 eyes C-MICS. Corneal aberrations were derived from conversion of the corneal elevation profile into corneal wavefront data with 6.0  mm aperture diameter using Zernike polynomials by corneal topography preoperatively and 1 month postoperatively. Both magnitude and axes of surgically induced corneal aberrations were calculated. RESULTS Mean final incision widths were 1.80 ± 0.09  mm and 1.89 ± 0.11  mm (p = 0.062) in B-MICS and C-MICS groups, respectively. There were no significant changes in total and higher order root mean square in both groups postoperatively. In B-MICS group, all aberration terms were similar, before and after surgery. However, vertical coma (p = 0.002), vertical trefoil (p < 0.001) and primary trefoil (p = 0.042) significantly increased postoperatively in the C-MICS group. Except surgically induced trefoil (p = 0.047), there was no significant difference in all surgically induced corneal aberrations between groups. The axes of the induced trefoil were found to be mostly related and close to the incision site in both groups which was more prominent in the C-MICS group. CONCLUSIONS Microincision cataract surgery techniques performed through sub-1.9  mm clear corneal incisions do not generally degrade optical quality of the cornea while only small amount of higher order aberrations seem to be induced with C-MICS technique.