Surgically induced astigmatism after biaxial phacoemulsification compared to coaxial phacoemulsification

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.

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).

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.

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.