Four-year visual outcomes and optical quality of SMILE and implantable collamer lens V4c (EVO-ICL) implantation for high myopia: a retrospective study

BackgroundTo compare the 4-year visual outcomes of implantable collamer lens V4c (EVO-ICL) implantation and small incision lenticule extraction (SMILE) for high myopia and astigmatism.MethodsThis retrospective case study included 64 eyes of 40 patients. These patients with preoperative manifest refraction spherical equivalent (SE) between - 6.00 and - 10.00 diopters (D) were screened from the database of SMILE and EVO-ICL implantation procedures in 2015. The ICL group [32 eyes of 19 patients (mean age, 29.6 & PLUSMN; 6.3 years); mean SE, -8.71 & PLUSMN; 1.06 D] and SMILE group [32 eyes of 21 patients (mean age, 27.7 & PLUSMN; 5.6 years); mean SE, -8.35 & PLUSMN; 0.65D] were compared. All patients were then prospectively examined at a four-year follow-up for routine postoperative examinations, higher-order ocular aberrations, retinal image quality and a questionnaire.ResultsThe safety indexes were 1.15 & PLUSMN; 0.14 and 1.22 & PLUSMN; 0.21 (P = 0.36) for the SMILE and ICL groups, respectively. No eyes lost two or more lines of CDVA in either group. The efficacy indexes were 0.97 & PLUSMN; 0.16 and 0.96 & PLUSMN; 0.19 (P = 0.87), respectively. Twenty-three eyes (72%) in ICL and 26 eyes (81%) in SMILE groups were within & PLUSMN; 0.5 D of the attempted SE (P < 0.01). ICL-treated eyes had significantly less spherical aberration and coma (P < 0.01 and < 0.05, respectively) postoperatively. Halos were the prevalent visual disturbance in both groups.ConclusionSMILE and EVO-ICL implantation provided safe and effective correction of high myopia. SMILE showed slightly better long-term predictability. Mild postoperative visual disturbances were observed after ICL and SMILE at 4-year follow-up.