Longitudinal Higher-Order OCT Assessment of Quantitative Fluid Dynamics and the Total Retinal Fluid Index in Neovascular AMD

Purpose The purpose of this study was to evaluate the feasibility of assessing quantitative longitudinal fluid dynamics and total retinal fluid indices (TRFIs) with higher-order optical coherence tomography (OCT) for neovascular age-related macular degeneration (nAMD). Methods A post hoc image analysis study was performed using the phase II OSPREY clinical trial comparing brolucizumab and aflibercept in nAMD. Higher-order OCT analysis using a machine learning-enabled fluid feature extraction platform was used to segment intraretinal fluid (IRF) and subretinal fluid (SRF) volumetric components. TRFI, the proportion of fluid volume against total retinal volume, was calculated. Longitudinal fluid metrics were evaluated for the following groups: all subjects (i.e. treatment agnostic), brolucizumab, and aflibercept. Results Mean IRF and SRF volumes were significantly reduced from baseline at each timepoint for all groups. Fluid feature extraction allowed high-resolution assessment of quantitative fluid burden. A greater proportion of brolucizumab participants achieved true zero and minimal fluid (total fluid volume between 0.0001 and 0.001mm3) versus aflibercept participants at week 40. True zero fluid during q12 brolucizumab dosing was achieved in 36.6% to 38.5%, similar to the 25.6% to 38.5% during the corresponding q8 aflibercept cycles. TRFI was significantly reduced from baseline in all groups. Conclusions Higher-order OCT analysis demonstrates the feasibility of fluid feature extraction and longitudinal volumetric fluid burden and TRFI characterization in nAMD, supporting a unique opportunity for fluid burden assessment and the impact on outcomes. Translational relevance Detection and characterization of disease activity is vital for optimal treatment of nAMD. Longitudinal assessment of fluid dynamics and the TRFI provide important proof of concept for future automated tools in characterizing disease activity.