Effect of biaxial versus coaxial microincision cataract surgery on optical quality of the cornea

CONTEXT: Visual function is determined by a combination of the cornea, which has a larger effect and internal aberrations generated by the intraocular lens and those induced by the surgery. These corneal refractive changes are related to the location and size of the corneal incision. The smaller the incision, the lower the aberrations and the better the optical quality. AIMS: To compare the effect of uneventful coaxial versus biaxial microincision cataract surgery (MICS) on the corneal aberrations. SETTINGS AND DESIGN: Retrospective interventional nonrandomized comparative case study comprised 40 eyes of 36 patients with primary senile cataract. SUBJECTS AND METHODS: They were divided into two groups: Group I (20 eyes) had operated by biaxial MICS and Group II (20 eyes) had operated by coaxial MICS. Each group were assessed by corneal topography and wavefront analysis over 6 mm pupil size preoperatively and 1-month postoperatively. STATISTICAL ANALYSIS USED: Statistical analysis was performed using SPSS for Windows (version 17.0.1, SPSS, Inc.). The paired t-test was used to compare the mean values of corneal aberrations preoperatively and 1-month postoperatively in each group. RESULTS: There was a significant increase in trefoil and quatrefoil in biaxial MICS (P = 0.063, 0.032 respectively) while other aberrations insignificantly changed. The coaxial MICS showed a significant increase in root mean square (RMS) of total high order aberrations (HOAs) (P = 0.02) and coma (0.028), but not the others. In comparison to each other, there was the insignificant difference as regards astigmatism, RMS of individual and total HOAs. CONCLUSIONS: Coaxial and biaxial MICS are neutral on corneal astigmatism and aberrations.