PURPOSE: To compare visual outcomes and optical quality of femtosecond laser–assisted small incision lenticule extraction (SMILE) and Visian Implantable Collamer Lens (ICL V4c; STAAR Surgical) implantation for moderate to high myopia. METHODS: For this systematic review and meta-analysis, the Cochrane, PubMed, Embase, and Chinese databases (Wan-fang data and CNKI) were comprehensively searched to identify studies comparing SMILE and ICL V4c implantation. Data of interest were extracted and analyzed by Stata V.16.0 software (StataCorp). The weighted mean differences and their 95% confidence intervals were used to assess the strength of the association. RESULTS: Twelve studies incorporating 1,390 eyes of 822 patients were included. The analysis revealed ICL V4c implantation had a significantly higher safety index and lower high order aberrations, coma, and spherical aberration than SMILE in treating moderate to high myopia ( P < .05). Subgroup analysis revealed such differences were more prominent in patients with high myopia who had shorter follow-up duration. When follow-up was longer than 6 months, the differences in safety index and total HOAs became nonsignificant ( P > .05). The two procedures had no difference in efficacy index, postoperative visual acuity, spherical equivalent, trefoil, Objective Scatter Index, or modulation transfer function cut-off frequency ( P > .05). CONCLUSIONS: Both SMILE and ICL V4c implantation were safe and efficient for moderate to high myopia. Compared with SMILE, ICL V4c implantation might provide better postoperative visual quality in patients with high myopia in the early postoperative period. [ J Refract Surg . 2022;38(6):332–338.]

BackgroundObtaining an ideal vault is crucial in the implantable collamer lens (ICL) surgery. Prediction of the vault value is difficult since it requires the integration of multiple factors. The purpose of this study was to investigate the association between the iris shape and vault value in eyes with thick lens.MethodsThe study was conducted in Peking Union Medical College Hospital. Patients who received ICL V4c between 2017 and 2021 were screened. Eyes with thick lens (&gt;4.0 mm) and abnormal iris shape (concave or convex) were included. The preoperative biometric parameters and postoperative vault value were compared between eyes with concave shape group and convex shape group. The relationship between various factors and vault was assessed by spearman rank analysis and multiple linear regression analysis. Representative cases our strategies to deal with the abnormal vault were demonstrated.ResultsTwenty eight eyes of 14 patients with thick lens and concave or convex shape iris were eventually included, with 14 eyes of 7 patients in group 1 (concave shape iris) and the other 14 eyes of 7 patients in group 2 (convex shape iris). The mean vault of group 1 was (0.16 ± 0.07) mm, which was significantly lower than (0.88 ± 0.13) mm in group 2. Multiple linear regression analysis showed iris shape (P &lt; 0.001) was only the explanatory variables associated with the postoperative vault. In group1, 4 eyes showed extremely large ACA, requiring a secondary surgical intervention. So all of them underwent ICL exchange for a larger ICL. In group2, the ICL was implanted in a vertical or oblique position to avoid or rescue an extremely large vault.ConclusionConcave shape iris had a higher risk of low vault and convex shape iris were more likely to demonstrate high vault in eyes with thick lens. Exchanging ICL for the larger size and adjusting ICL to the vertical or oblique orientation are good option to rescue the low or high vault, respectively.