Quantitative Ciliary Body Imaging Using Image-Registered Swept-Source AS-OCT and Ultrasound Biomicroscopy.

PURPOSE: The purpose of this study was to evaluate inter- and intra-device agreement of ciliary body (CB) biometric parameters measured by image-registered swept-source anterior segment optical coherence tomography (AS-OCT; ANTERION, Heidelberg Engineering, Heidelberg, Germany) and ultrasound biomicroscopy (UBM; Insight 100, ArcScan). METHODS: Patients undergoing anterior segment imaging were prospectively enrolled. Horizontal scans were acquired under standardized illumination. One eye per participant was randomly selected for analysis. Maximum ciliary muscle thickness (CMTMAX), maximum CB thickness (CBTMAX), sulcus-to-sulcus (STS) distance, and scleral spur-to-scleral spur (SSS) distance were manually measured. Eyes with pupillary diameter differences ≥15% were excluded. Inter- and intra-device agreement were assessed using intraclass correlation coefficients (ICCs), linear regression, and Bland-Altman analysis. RESULTS: Seventy-eight eyes from 78 subjects (mean age = 61.9 ± 12.6 years) were analyzed. Inter-device agreement was good to excellent (ICC = 0.60-0.85). Mean absolute inter-device differences were 57.6 ± 36.6 µm for CBTMAX, 40.6 ± 44.7 µm for CMTMAX, 0.28 ± 0.23 mm for SSS, and 0.18 ± 0.16 mm for STS; corresponding mean absolute relative inter-device differences were 4.8% for CBTMAX, 5.9% for CMTMAX, 1.5% for SSS, and 2.5% for STS. Greater baseline CBTMAX was the only factor consistently associated with inter-device differences in CBTMAX or CMTMAX (P < 0.001). Intra-device repeatability was excellent across all parameters for both systems (ICC = 0.78-0.90 for ANTERION and 0.80-0.94 for Insight). CONCLUSIONS: Image-registered AS-OCT and UBM provided largely concordant and highly repeatable CB measurements, although systematic inter-device differences across the two modalities suggest they cannot be considered fully interchangeable. TRANSLATIONAL RELEVANCE: Modern image-registered swept-source AS-OCT provides a viable, non-contact alternative to UBM for quantitative CB assessment.