Study: Greater astigmatic reductions with paired vs. single corneal incisions

Paired opposite clear corneal incisions better reduce pre-existing astigmatism than a single incision, according to a study by researchers in India.

Sudarshan Khokhar, MD, and colleagues at the Rajendra Prasad Centre for Ophthalmic Sciences, New Delhi, prospectively compared the two incisional approaches in 40 eyes of 40 cataract patients. All patients had pre-existing astigmatism greater than 1.5 D.

The researchers randomly assigned patients to treatment with either paired 3.2-mm opposite clear corneal incisions (OCCI) or a single 3.2-mm clear corneal incision (CCI) before performing phacoemulsification. All incisions were made on the steep axis, according to the study.

The researchers found significant astigmatic reductions in both groups. At 12 weeks' follow-up, astigmatism decreased from 2.51 ± 0.92 D preoperatively to 0.91 ± 0.54 D among eyes treated with paired incisions; astigmatism decreased from 2.17 ± 0.81 D to 1.57 ± 0.7 D among eyes treated with a single incision.

Eyes treated with paired incisions had a significantly higher astigmatic reduction, averaging 1.6 ± 0.45 D compared with 0.59 ± 0.43 D for eyes treated with a single incision (P = .00), according to the study.

Both groups showed significant reductions in surgically induced astigmatism, averaging 1.66 ± 0.5 D for eyes treated with paired incisions and 0.58 ± 0.75 D for eyes treated with a single incision.

Eyes treated with the paired incision showed better postoperative uncorrected visual acuity, but there was no difference in best corrected visual acuity between the two groups, the study authors noted.

"An identical CCI opposite the first CCI enhances the flattening effect on the cornea ... OCCIs are self-sealing, pose no added risk, require no extra surgical equipment and are effective in treating pre-existing astigmatism," they said.

The study is published in the September issue of the Journal of Cataract & Refractive Surgery.