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

Background: To 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.

Methods: This 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 ± 6.3 years); mean SE, -8.71 ± 1.06 D] and SMILE group [32 eyes of 21 patients (mean age, 27.7 ± 5.6 years); mean SE, -8.35 ± 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.

Results: The safety indexes were 1.15 ± 0.14 and 1.22 ± 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 ± 0.16 and 0.96 ± 0.19 (P = 0.87), respectively. Twenty-three eyes (72%) in ICL and 26 eyes (81%) in SMILE groups were within ± 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.

Conclusion: SMILE 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.