Long-term outcome and related-risk factors in Implantable Collamer Lens (ICL) Implantation of high myopia.

Purpose: To investigate the long-term efficacy and safety of posterior chamber implantable collamer lens (ICL) implantation in high myopia, and the risk factors associated with endothelial cell loss (ECL) or cataract development.

Methods: Medical records of 66 eyes of 37 patients who underwent ICL implantation for high myopia were retrospectively analyzed with a mean follow-up of 12 years. Changes in LogMAR best corrected visual acuity (BCVA), intraocular pressure (IOP), refractive power, and endothelial cell density (ECD) over time were analyzed with the incidence of cataract and IOP elevation. Risk factors were analyzed for their association with ECL or cataract development.

Results: At 10 years after surgery, the mean uncorrected visual acuity (UCVA) was 0.06 and the spherical equivalent (SE) was -0.90 D. By year 10, cataract was present in 19% (13/64), whereas glaucoma was found in 1.5% (1/64). Although IOP continuously elevated over time (p<0.05), it remained within normal limits. The cataract group had a lower vault of ICL and a higher mean age at surgery (P<0.05). ECD remained above 2000/mm² in 98.5% of cases, with an average annualized rate of decline of 1.13%. The high annualized rate group (>1.13% loss/year) had a lower mean age than in the low annualized rate group (vs < 1.13% loss/year, P<0.05).

Conclusion: This indicates that ICL implantation is effective for high myopia, and its main complication is cataract and ECL. It also suggests that ECL and cataract should be regularly monitored although ECL looks stable in long-term follow-up. Age may affect both ECL and cataract, while low-vault ICL may affect cataract.