Correlation Between Anterior Chamber Angle Reduction And Vault Dynamics Following Implantable Collamer Lens Surgery: Implications For Visual Outcomes

To elucidate the biomechanical relationship between anterior chamber angle (ACA) reduction and vault dynamics following V4c implantable collamer lens (ICL) surgery, and establish their collective impact on visual outcome optimization in myopia correction.

Multicenter retrospective cohort study analyzing 1,169 eyes from 589 consecutive myopic patients undergoing V4c ICL implantation with 3-month postoperative follow-up at tertiary refractive centers.

Preoperative assessments included swept-source OCT (Casia2, Tomey) measurements of ACA (39.31±5.02°) and sulcus-to-sulcus dimensions (horizontal 11.6±0.42 mm, vertical 12.16±0.47 mm). Postoperative evaluations incorporated dynamic anterior segment OCT (Visante, Zeiss) for vault quantification (740.61±269.55 μm) and Scheimpflug imaging (Pentacam HR, Oculus) for ACA analysis (13.46±4.77°). Multivariable linear regression models adjusted for ICL size, patient age, and anterior chamber volume were employed to identify predictive factors.

The cohort demonstrated significant refractive improvement with mean spherical equivalent reduction of -10.25±2.78D (p<0.001). A strong inverse correlation emerged between ACA reduction and vault elevation (r=-0.82, p<0.001), mathematically defined as ΔACA(°)=0.11×Vault(μm)+6.8 (R²=0.67). ICL sizing critically influenced angle configuration, with each 0.5mm increase in implant diameter associated with 3.2° greater ACA reduction (β=0.43, p=0.002). Eyes achieving angle-vault equilibrium (350-800μm vault with 12-18° ACA) demonstrated superior visual outcomes (≥20/25 in 96.1% vs 82.3% in non-equilibrium group, p=0.009).

This study establishes three key principles: 1) ICL-induced ACA reduction directly correlates with vault through anterior segment remodeling 2) Implant sizing significantly modulates angle configuration 3) Angle-vault equilibrium (350-800μm/12-18°) optimizes visual outcomes. We propose a paradigm shift incorporating computational modeling of angle-vault interactions during preoperative planning, particularly for large ICL sizes (>13.2mm). Dynamic OCT monitoring should be prioritized to maintain biomechanical equilibrium and prevent angle-related complications.