Macular fibrosis in neovascular AMD: inter-reader and intermodality variability across four imaging modalities

Objective: To assess inter-reader and intermodality variability in quantifying macular fibrosis in patients with neovascular age-related macular degeneration (AMD) using 4 imaging modalities: color fundus photography (CFP), near-infrared reflectance (NIR), structural optical coherence tomography (OCT), and MultiColor imaging. Design: Prospective, cross-sectional case series. Participants: Thirty eyes of 30 patients with neovascular AMD and macular fibrosis, previously treated with anti-vascular endothelial growth factor therapy. Methods: Imaging was performed using CFP, NIR, structural OCT, and MultiColor modalities. Two masked graders evaluated the size of macular fibrosis using each modality. The study assessed inter-reader agreement using the intraclass correlation coefficient (ICC), coefficient of variation (CV), and 95% coefficient of repeatability. Intermodality variability was analyzed using repeated measures ANOVA and pairwise comparisons. Results: Structural OCT demonstrated the highest inter-reader agreement (ICC = 0.983; CV = 0.04), while NIR exhibited the lowest (ICC = 0.461; CV = 0.26). The median macular fibrosis size was largest on structural OCT (4.87 mm²) and smallest on MultiColor imaging (2.03 mm²). Significant differences were observed between imaging modalities, with fibrosis measurements from different modalities not consistently comparable. Conclusions: Structural OCT is the most reliable modality for quantifying macular fibrosis in neovascular AMD. The observed intermodality variability highlights the need for standardized criteria in fibrosis assessment across imaging techniques, as differences can impact clinical interpretation and management.