Fifteen-year follow-up of implantable collamer lens surgery in high myopia: Complications, cataract surgery outcomes, and ultrastructural analysis.

PURPOSES: This study reports 15-year outcomes of implantable collamer lens (ICL) surgery in patients with high myopia, analyzing complications, efficacy of cataract surgical, and ultrastructural mechanisms of anterior subcapsular cataract (ASC). METHODS: This retrospective study included 1208 eyes (ICL V4) and 6258 eyes (ICL V4c) from Eye & ENT Hospital of Fudan University, Shanghai, China. Follow-ups occurred preoperatively, at 1/3/6 months, annually post-ICL, and 1 month post-cataract surgery. Lens opacity, ASC rates, and complications were evaluated. Anterior capsule ultrastructure was assessed using scanning/transmission electron microscopy (SEM/TEM). RESULTS: The ICL V4 group (follow-up: 23.12 ± 32.06 months) exhibited higher complication rates than V4c (8.95 ± 17.40 months): lens opacity (6.46% vs. 0.16%), ASC (2.32% vs. 0.10%), and bilensectomy (3.89% vs. 0.16%). Bilensectomy improved corrected distance visual acuity from 0.56 ± 0.39 to 0.34 ± 0.51 logMAR (P = 0.006), restoring pre-ICL levels (P = 0.310), with safety/efficacy indices of 1.08 ± 0.11 and 0.99 ± 0.08. Myopia-related complications included myopic macular atrophy (0.38%), choroidal neovascularization (0.24%), and retinal detachment (0.04%). SEM/TEM revealed lens epithelial cell proliferation, fibronectin or collagen deposition, and mitochondrial abnormalities (thickened cristae, perinuclear vacuolization) in ASC cases. CONCLUSIONS: Super high myopia, shallow anterior chamber depth, and older age are key risk factors for post-ICL cataract. While bilensectomy restores vision, high myopia-related complications persist. ASC pathogenesis involves mechanical damage and metabolic dysfunction, evidenced by ultrastructural changes. These findings underscore the need for long-term monitoring in ICL patients with high myopia.