Anterior Segment Characteristics Changes After Implantable Collamer Lens V4c in Low Anterior Chamber Depth Eyes: An Optical Coherence Tomography Study

Purpose To investigate anterior segment changes after implantable collamer lens V4c (ICL-V4c; STAAR Surgical) implantation in eyes with low anterior chamber depth (ACD) and compare them with eyes with normal ACD. Methods This prospective, interventional case-control study included 96 eyes of 48 patients with a low ACD (< 2.8 mm) and 44 eyes of 22 patients with normal ACD (≥ 2.8 mm) receiving a 12.1-mm ICL. All patients underwent follow-up and comprehensive ophthalmic examinations preoperatively and at 1, 3, and 6 months after surgery. Anterior segment parameters, including ACD, anterior chamber width, crystalline lens rise, anterior chamber angle, trabecular-iris angle (TIA), angle opening distance, trabecular-iris space area, the distance from cornea to ICL, and vault were all conducted by optical coherence tomography. These parameters from the last follow-up (6 months postoperatively) were used for statistical analysis to assess changes in anterior segment structure and their relationship with vault height. Results The mean safety and efficacy index in eyes with low ACD were 1.23 ± 0.22 and 1.21 ± 0.08 respectively. In both groups, anterior chamber structure parameters become narrower compared to preoperatively (all P < .05). Preoperative ACD and C-ICL demonstrated significant correlations with ICL vault in eyes with low ACD ( P < .001). Compared with eyes with normal ACD preoperatively, eyes with low ACD are more prone to have low vault ( P < .01). There is a correlation between normal vault and corneal horizontal white-to-white distance ( P = .032), ACD ( P = .046), and temporal TIA 500 ( P = .016). Conclusions ICL-V4c surgery in eyes with low ACD is safe and efficacious. In patients with low ACD, the normal vault could be better anticipated by considering preoperative anterior chamber angle, white-to-white distance, and ACD. [ J Refract Surg . 2025;41(4):e342–e355.]