Surgically induced astigmatism after biaxial phacoemulsification compared to coaxial phacoemulsification

Abstract

Purpose: A comparison of the topographic astigmatism generated after coaxial phacoemulsification (CP) through temporal 2.8 mm incision and biaxial phacoemulsification (MICS) through superior-oblique trapezoidal 1.5-2 mm incisions.

Setting: Centre for Visual Sciences (Instituto de Ciencias Visuales, INCIVI), Madrid, SpainMethods This prospective randomized clinical study included 94 eyes of 64 patients; 43 eyes were operated on through CP and 51 through MICS. Corneal topography was measured before operation, and subsequently after 1, 3, and 6 months. Additionally, a control group (C) of 55 eyes was created (performing two topographies on them); the change in astigmatism was calculated without having performed any surgical procedure. The astigmatic change in the three groups was measured through arithmetic, polar and vector analysis (Alpins method).

Results: In the vector analysis, results after the first month following surgery were: mean module of the surgically induced astigmatism (SIA) 0.49+/-0.38 D in CP and 0.48+/-0.37 D in MICS, while 0.31+/-0.27 D in group C. Although no statistically significant differences were detected between the two surgical techniques, differences were noted when comparing group C with each of these techniques (P<0.05). The distribution of the SIA axes showed a slight tendency to be located more frequently at around 90 degrees in CP, and at around 50 degrees in MICS.

Conclusions: The mean module of SIA was similar in CP and in MICS, although the distribution of the direction of such a vector revealed minor differences.