Size exchange and vault response in posterior chamber phakic intraocular lens implantation: 12 years at a high-volume center

Abstract

Purpose: To evaluate vault change after implantable collamer lens (ICL) exchange and identify outcome predictors, emphasizing age effects. Setting: High-volume refractive surgery center, South Korea. Design: Single-center retrospective cohort. Methods: Records of ICL implantations (2013 to 2024) were reviewed. Eyes requiring exchange were classified upsizing, same-size, or downsizing. Primary outcome: 6-month vault change; secondary: endothelial cell density (ECD). Indications for exchange and age-vault relationships were assessed. Results: Of 22 739 eyes, 110 (0.48%) underwent exchange: upsizing 70, same-size 27, downsizing 13. Indications differed by group: downsizing for high vault (13/13, 100%); upsizing for low vault (24/70, 34.3%) or toric rotation (44/70, 62.9%); same-size for residual refraction (17/27, 63.0%) or toric status change (10/27, 37.0%). Upsizing increased vault from 311.6 +/- 223.0 & micro;m to 481.0 +/- 278.6 & micro;m (Delta +169.4 & micro;m; P < .001), with smaller gains at age 35 years or older. Downsizing reduced vault from 1284.2 +/- 240.7 & micro;m to 539.1 +/- 176.1 & micro;m (Delta-745.1 & micro;m; P < .001), restoring 12 of 13 eyes (92.3%) to a prespecified safe range. Same-size exchange produced a small decrease (Delta-62.8 & micro;m; P = .043). Across upsizing and downsizing, older age is linked to vault reduction, yielding smaller gains after up-sizing (P = .013) and larger decreases after downsizing (P = .017). ECD showed small but significant declines across all groups (P < .050). Conclusions: Vault change after ICL exchange was strategy-dependent: downsizing reliably reduced excessive vault, same-size exchange produced minimal change, and upsizing yielded smaller gains that diminished with increasing age. ICL exchange requires careful planning that accounts for exchange strategy, preoperative vault, and patient age. Copyright (c) 2025 Published by Wolters Kluwer on behalf of ASCRS and ESCRS