Phacoemulsification With 3.0 and 2.0 mm Opposite Clear Corneal Incisions for Correction of Corneal Astigmatism.

PURPOSE: To compare the effect of 3.0 and 2.0 mm opposite clear corneal incisions (OCCIs) in phacoemulsification on reduction of preexisting corneal astigmatism, and their impact on corneal aberrations.

METHODS

This study is a prospective randomized controlled study that included 140 patients with age-related cataract and regular corneal astigmatism ≥0.75 diopter (D). Phacoemulsification was performed using on-meridian 3.0 or 2.0 mm corneal incision with or without an OCCI. Cases were divided into 4 groups: 3.0 mm OCCIs, 3.0 mm single clear corneal incision (3.0 mm SCCI), 2.0 mm OCCIs, and 2.0 mm SCCI. Keratometry and topography were performed at 3 months postoperatively. The variations in corneal astigmatism and aberrations were recorded. Surgically induced astigmatism was calculated using vector analysis.

RESULTS

The corneal astigmatism reduction was 0.61 ± 0.38 D in the 3.0 mm OCCIs group, significantly higher than the other groups (P ≤ 0.004); and 0.29 ± 0.29 D in the 2.0 mm OCCIs group. The mean surgically induced astigmatism was 1.07 ± 0.51 D in the 3.0 mm OCCIs group, higher than 0.61 ± 0.35 D in the 2.0 mm OCCIs group (P = 0.001). The root mean square values of corneal trefoil, spherical aberration, and total higher order aberrations increased at 3 months postoperatively, but there were no significant differences between OCCI and SCCI groups.

CONCLUSIONS

On-meridian 3.0 mm OCCIs are effective for correcting mild-to-moderate corneal astigmatism during cataract surgery, exerting no additional impact on corneal aberration compared with SCCI.