Visual and refractive outcomes of a combined opposite clear corneal incision procedure

A significant difference was detected in residual astigmatism and anterior corneal keratometric astigmatism between patient groups. Image credit: ©Oktay – stock.adobe.com

A team of researchers in China conducted a study to evaluate the visual and refractive outcomes of astigmatic cataract patients following treatment with an opposite clear corneal incision (OCCI) combined with rotationally asymmetric multifocal intraocular lens (IOL) implantation.

The researchers are from the Department of Ophthalmology, Zhongshan Hospital (Xiamen), Fudan University, Xiamen, China and the Center for Evidence-based Medicine, Fudan University, Shanghai, China.

The retrospective cohort study included patients with corneal astigmatism who underwent phacoemulsification and rotationally asymmetric multifocal IOL implantation, treated with either an OCCI (OCCI group) or a single clear corneal incision (SCCI).¹

“In this study, we aim to investigate the efficacy and safety of the technique by comparing the visual and refractive outcomes of a group of cataract patients with or without an OCCI during phacoemulsification and rotationally asymmetric multifocal IOL implantation,” investigators wrote.

Patients underwent phacoemulsification and rotationally asymmetric multifocal IOL implantation (Lentis Comfort LS-313 MF15, Teleon GmbH) from 1 December, 2022, to 30 April, 2023, at Zhongshan Hospital. The patients were 50 years or older with a preoperative magnitude of manifest astigmatism ≥ 0.5 diopter (D), and a preoperative magnitude of corneal astigmatism between 0.50 and 3.00 D.

In total, 58 eyes of 54 patients were enrolled in this study. These patients were separated into two groups based on whether they were treated with an OCCI or an SCCI surgical procedure.¹

An experienced surgeon performed all the surgeries, and proparacaine hydrochloride eye drops (Alcaine, Alcon) were administered to induce surface anesthesia. The surgical procedures differed between the two groups when performing corneal incisions.

In the OCCI group, limbal marks were made prior to surgery at the 3 and 9 o’clock positions on the cornea with patients sitting in front of the slit-lamp and looking straight ahead to avoid cyclotorsion. Patients underwent a topographic examination (Oculus 77000) before surgery. The axis position of the maximal keratometry value from the axial map was selected as the main incision position.

In the SCCI group, limbal marks were not required. The incisions were made at the 11 and 1 o’clock positions (2.4 and 1 mm in width, respectively).

Excluding OCCI and SCCI, the remaining surgical procedures were identical between groups.¹

According to the researchers, the follow-up period was 3 months postoperatively. They accessed distance, intermediate and near visual acuity, refractive outcomes and corneal anterior keratometry between the two groups. A vector analysis was used to evaluate the astigmatism correction.

The researchers found that 3 months after surgery, the distance, intermediate and near visual acuity remained comparable between the two groups, as did sphere. However, a significant difference was detected in residual astigmatism and anterior corneal keratometric astigmatism. In the OCCI group, the residual astigmatism and keratometric astigmatism were −0.60 ± 0.29 D and 0.59 ± 0.28 D, respectively, which were lower than those in the SCCI groups (−1.18 ± 0.47 D and 1.15 ± 0.45 D, both p < 0.05). In vector analysis, the difference vector, angle of error (AoE), absolute AoE, index of success and correction index were statistically significantly different between the groups (p < 0.05).¹

The researchers noted that the OCCI combined with rotationally asymmetric multifocal IOL implantation showed predictable and desirable efficacy in treating cataract patients with astigmatism.

“The current study confirms that incisions placed at the steep K meridian can safely reduce residual astigmatism after cataract surgery,” the researchers concluded. “Corneal curvature optimised incision planning, specifically opposite the clear corneal incision, and combined with rotationally asymmetric multifocal IOL implantation provides optimal visual and refractive outcomes.”

The authors declare that financial support was received for the research, authorship, and/or publication of the article. Their work was supported by Xiamen Municipal Natural Science Foundation (No. 3502Z20227277). It was also supported by the Science and Technology Project of Xiamen (No. 3502Z20224ZD1076). The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.¹

Reference

1. Qin X, Yao P, Wu X, et al. Visual and refractive outcomes of opposite clear corneal incision combined with rotationally asymmetric multifocal intraocular lens implantation. Frontiers in medicine. 2024;11. doi:https://doi.org/10.3389/fmed.2024.1389186

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