opposite clear corneal incisions versus on-axis incision during phacoemulsification to correct pre-existing astigmatism

purpose: to compare the efficacy of adding an opposite clear corneal incision (occi) on the steep axis during phacoemulsification in reducing the pre-existing corneal astigmatism. methods: this randomized clinical trial was performed on 120 eyes with corneal astigmatism of >1d undergoing phacoemulsification. incisions were made based on the type of astigmatism as follows: superior or superior+occi in the with-the-rule and temporal or temporal+occi in the against-the-rule astigmatism. patients were followed with refraction, keratometry and topography. statistical analyses were done using one and two ways anova and tukey-a test. results: mean corneal astigmatism was 1.82±0.86 d in the superior+occi group and 1.74±0.86 d in the temporal+occi group preoperatively which respectively decreased to 1.31±0.59 (p= 0.013) and 1.19±0.64 (p= 0.009) postoperatively. no significant changes occurred in the amount of astigmatism in none of the two single incision groups. conclusion: paired occi on steep axis is a useful technique to correct mild to moderate pre-existing astigmatism with no need to extra skill or instrumentation.