Clinical course of non-exudative macular neovascularisations in sustained unilateral neovascular age-related macular degeneration

PURPOSE: To assess the risk of conversion of non-exudative macular neovascularisations (NEMNV) in relation to disease history in sustained unilateral neovascular age-related macular degeneration (AMD). METHODS: This exploratory case-only cohort study included six-monthly visits. Fellow-eye NEMNV were identified using fluorescein and indocyanine green angiography. Patients were stratified by time since first-eye exudation: < 5 years (G1) or ≥ 5 years (G2). The primary outcome was the cumulative annual conversion rate of NEMNV, expressed as conversion rate ratios (CRR) with 95% confidence intervals (CI). Secondary outcomes were independent grading of foveal involvement, core vessel, central core vessel, round shape, sharp borders, and lesion growth. RESULTS: A total of 134 patients (65.7% female) were included. Mean age at baseline was 74.2 years (SD 8.0). Median time since first-eye exudation was 2.9 years (IQR 1.0-6.3). Patients in G2 had an earlier age at first-eye exudation (66.0 [9.1] years) than G1 (72.7 [7.8]; P < .001). Seven NEMNV lesions were identified (G1:2, G2:5). Cumulative conversion rates were 22.1% overall, 14.3% in G1, and 27.1% in G2. CRR were 2.3 (95% CI 0.6-6.2), 1.3 (95% CI 0.0 - 7.8), and 4.0 (95% CI 0.7 - 16.8). All but one NEMNV showed growth. CONCLUSION: In this limited sample, most NEMNV show growth time regardless of conversion to exudative AMD and appear at a higher risk of conversion. The rate of conversion varies with the age of onset of first-eye exudation. Evaluating potential predictive signs of conversion may benefit from incorporating disease history with vascular features.