Risk Factors Associated With ICL Decentration After ICL Surgery

To evaluate the magnitude and direction of Implantable Collamer Lens (ICL V4c; STAAR Surgical) decentration at 1 month after implantation and to identify associated preoperative biometric factors.

This prospective observational study included 52 patients (104 eyes) receiving ICL V4c implantation. Preoperative measurements included corneal curvature, anterior chamber depth, white-to-white distance, axial length, and angle alpha and angle kappa. One month postoperatively, total, horizontal, and vertical decentrations of the ICL center relative to the visual axis were measured using the OPD-Scan III (Nidek). Generalized estimating equations (GEEs) were used to analyze relationships between decentration and biometric variables while accounting for inter-eye correlation.

The mean total decentration was 0.43 ± 0.19 mm and was predominantly temporal; mean horizontal and vertical decentrations were -0.24 ± 0.32 and 0.05 ± 0.24 mm, respectively. GEE analysis showed that the magnitude of angle alpha was significantly correlated with total decentration (coefficient = 0.669, β = 0.422; adjusted R² = 0.159; P < .001), that horizontal decentration was related to the horizontal components of angles alpha and kappa (adjusted R² = 0.415), and that vertical decentration was related to the vertical component of angle kappa (adjusted R² = 0.075). Eyes with angle alpha greater than 0.50 mm exhibited greater decentration.

ICL decentration after surgery is generally small but varies between individuals; angle alpha is the main predictor of decentration, and preoperative measurement of angles alpha and kappa helps identify patients at higher risk.