Long-term Evolution and Growth Rate Assessment of Non-Exudative Macular Neovascularization: A Multicenter Analysis

Purpose: A population of patients with age-related macular degeneration (AMD) was analyzed to investigate the prevalence of non-exudative macular neovascularizations (neMNV), the conversion rate to exudation, and to discern differences between neMNVs that exhibited exudation versus those that remained non-exudative. Design: Retrospective observational case series. Methods: In this retrospective, multicentric, longitudinal study, consecutive patients treated with anti-VEGF between august 2008 and June 2023, presenting exudative AMD in one eye and intermediate AMD in the fellow eye, were analyzed. The presence of neMNVs in the fellow eyes and their conversion rate to exudation were assessed. Clinical and anatomical features were compared between eyes that developed exudation versus those that did not. The correlation between lesion major diameters and areas was examined to evaluate their equivalence as parameters for assessing neMNV growth rate. Results: A total of 61 eyes out of 840 (7.3%) exhibited neMNV. Of these, 21 neMNV (34.42%) converted to exudation in a mean time of 24.14 months (min. 7 - max. 113). The remaining 40 eyes did not develop exudation during a mean follow-up of 32.5 months (min. 12 - max. 101). No significant differences were found regarding visual acuity, OCT angiography features, or baseline lesion diameters. NeMNV that developed exudation exhibited a higher lesion growth rate (p-value <0.001). The growth rate evaluated using lesion major diameters was consistent with that obtained through lesion area measurements. Conclusion: The results highlight lesion growth rate as a marker of conversion risk. Lesion diameter was identified as a reliable parameter for monitoring neMNV progression. Despite a long-term follow-up, many lesions did not develop exudation. These results support the idea that neMNV may represent a spectrum of neovascularizations with different characteristics and clinical courses.