Visual Quality After Implantable Collamer Lens Implantation With A Modified Steep-Meridian Corneal Relaxing Incision For Correction Of Astigmatism

To investigate the visual outcomes and optical quality of a modified steep-meridian corneal relaxing incision (MS-CRI) for correcting astigmatism in implantable collamer lens (ICL) surgery.

Affiliated Eye Hospital of Nanchang University, China

The prospective, interventional case series included 69 eyes of 37 consecutive patients with myopia and astigmatism who underwent EVO ICL implantation. The MS-CRI was performed on the steep meridian of subjective refraction, and the incision size was determined based on the preoperative cylinder. Refractive outcomes and corneal higher-order wavefront aberrations (HOA) were evaluated preoperatively and postoperatively at 2 weeks and 6 months. Vector analysis was performed.

Six months after surgery, the efficacy index was 1.12 ± 0.22 and the safety index was 1.18±0.19. Mean astigmatism decreased significantly from -1.32 ± 0.67 D preoperatively to -0.54 ± 0.43 D postoperatively. Surgically induced astigmatism (SIA) was 0.69 ± 0.50 D and keratometric SIA (SIA_k) was 0.82 ± 0.43 D. Correction index was 0.68±0.34 and magnitude of error was -0.38 ± 0. 45 D. Arithmetic mean angle of error (AE) was -1.59 ± 11.75° and 86% of eyes had an AE within ±15°. Corneal HOA increased significantly at 2 weeks after the surgery but no significant differences were observed in coma, trefoil, and spherical aberrations after 6 months. A significant correlation was found between the magnitude of target-induced astigmatism and SIA_k.

MS-CRI is a fast, acceptable, and safe technique for low and moderate astigmatism in ICL surgery, with a potential reduction in induced HOA over time; however, it is not the optimal choice for correcting high astigmatism.