Management of low astigmatism in implantable collamer lens surgery: opposite clear corneal incisions vs toric implantable collamer lens

Abstract

Purpose: To compare two techniques to correct low astigmatism during implantable collamer lens (ICL) surgery: astigmatic opposite clear corneal incisions (OCCIs) and toric ICL (T-ICL). Setting: Arruzafa Ophthalmological Hospital, Cordoba, Spain. Design: Randomized prospective comparative study. Methods: The study comprised 152 myopic eyes undergoing ICL (STAAR Surgical) surgery. Patients were separated into two groups: group 1 (57 patients; 76 eyes) received a spherical ICL with OCCIs and group 2 (53 patients; 76 eyes) received a T-ICL. The inclusion criteria were refractive astigmatism up to 1.50 diopters (D), regular corneal astigmatism up to 2.00 D (Sim K, Pentacam), and agreement between the refractive and topographic corneal cylinders (discrepancies less than 30º axis or 0.50 D). The outcomes were evaluated after a one-month follow-up. Results: The T-ICL group achieved a mean postoperative spherical equivalent refraction and refractive astigmatism of -0.04 ± 0.17 D and -0.03 ± 0.12 D, respectively, versus -0.14 ± 0.33 D and -0.20 ± 0.36 D, in the OCCI group (P<0.001). Postoperative refractive astigmatism of less than 0.25 D was achieved in 94.74% of cases in the T-ICL group versus 73.68% in the OCCI group. Undercorrection of corneal astigmatism occurred in the OCCI group with a surgically induced astigmatism of 0.48 ± 0.24 D and correction index=0.46. Conclusions: Both the T-ICL and OCCI techniques provided excellent results in terms of safety and efficacy. T-ICL surgery was shown to be more predictable and accurate for correcting low astigmatism with a lower postoperative spherical equivalent and less residual astigmatism compared to incisional management.