Efficacy comparison of moderate to severe astigmatism: implantable collamer lens combined with paired opposite clear corneal incisions versus toric implantable collamer lens

PURPOSE: To compare the efficacy of Implantable Collamer Lens (ICL) combined with paired opposite clear corneal incisions (OCCI) versus Toric Implantable Collamer Lens (TICL) for moderate to severe astigmatism. METHODS: This retrospective comparative study included 40 patients with moderate to severe astigmatism (cylinder 1·5D-3·0D). Based on patient preference, 20 eyes underwent TICL implantation (TICL group) and 20 eyes underwent ICL with OCCI (OCCI group). Preoperative and 6-month postoperative data were analyzed, including uncorrected and corrected distance visual acuity (UDVA, CDVA), refraction, higher-order aberrations (HOAs), and Alpins vector parameters (target-induced astigmatism [TIA], surgically induced astigmatism [SIA], difference vector [DV], correction index [CI], angle of error [AE]). RESULTS: At 6 months postoperatively, both groups showed significant visual improvement. The proportion achieving UDVA ≥ 20/20 was 100% in TICL group and 95% in OCCI group. Residual astigmatism ≤ 1·0D was achieved in 95% (TICL) and 90% (OCCI). Spherical equivalent within ±1·0D was 95% and 90%, respectively. OCCI induced significantly more HOAs, horizontal coma, and horizontal trefoil postoperatively compared to TICL (all p < 0.05). Vector analysis showed no significant between-group differences in TIA, SIA, DV, CI, or AE (all p > 0.05). CONCLUSIONS: ICL combined with OCCI yields acceptable visual and refractive outcomes for moderate to severe astigmatism, though slightly inferior to TICL in accuracy and HOAs. It represents a viable alternative when TICL is unavailable or contraindicated.