OCT Macular Volume as a Predictor of Vascular Leakage in Uveitis

This study aimed to evaluate the optical coherence tomography (OCT) macular volume as a marker for active vascular leakage in patients with intermediate and pan uveitis.In this single-center prospective longitudinal study, patients were included under three criteria: diagnosed with noninfectious intermediate or pan uveitis; presented vascular leakage at their initial visit; and were imaged with concurrent wide-field fluorescein angiography (FA) and OCT. A scoring system was employed to measure vascular leakage. OCT volume scans were performed on the patients to produce the corresponding thickness map. The central subfield thickness (CST) and macular volume (MV) were calculated. CST is defined as the average thickness within the 1-mm fovea circle, while MV includes the 3-mm and 6-mm circles on the thickness map. Mixed-effects models were applied to analyze the correlation between each patient's OCT and FA imaging results.A total of 72 patients (115 eyes) were included. The median follow-up time was 11 months (interquartile range 1.8-16.1 months). A total of 679 observations across all time points were analyzed. Both CST and MV were found to be positively associated with the leakage scores (p < 0.001). In the mixed-effects models, MV in the 6-mm circle presented the strongest correlation with leakage scores, which explained 57% of the variation in leakage (p < 0.001). MV in the 3-mm circle and CST explained 45.8% and 39.5%, respectively.CST and MV in both the 6-mm and the 3-mm circles demonstrated significant correlations with angiographic inflammatory activity. Among those imaging parameters, MV in the 6-mm circle has the highest correlation. The study results suggest that this parameter can be considered a quantitative and non-invasive alternative to FA for monitoring vasculitic inflammation in uveitis.