Morphological Biomarkers Predicting Exudative Conversion in Type 1 Nonexudative Macular Neovascularization Using OCT Angiography

Abstract

Purpose: To investigate the incidence and morphological biomarkers to predict the exudative conversion in eyes with type 1 nonexudative macular neovascularization (MNV) using swept-source optical coherence tomography angiography (SS-OCTA). Methods: MNVs were detected using the retinal pigment epithelium (RPE)-to-RPE-fit slab of SS-OCTA scan. Depending on whether exudation developed within a year, the eyes were divided into two groups: active and silent. Qualitative and quantitative OCTA parameters of the two groups were evaluated to discriminate the biomarkers associated with exudative conversion. Results: Of the 40 eyes, nine developed exudation within one year (incidence rate 22.5%). The active group exhibited significantly higher "anastomosis and loops" pattern, greater "vessel density," increased "junction density," fewer “number of endpoints,” and lower "lacunarity" compared to silent group. "Anastomosis and loops" and higher "vessel density" were correlated with the active group in multivariate analyses. A predictive model combining these biomarkers achieved 95% accuracy in predicting exudative conversion. Conclusion: At 12 months, the risk of exudation was 22.5%, and "anastomosis and loops" and "vessel density" were useful OCTA biomarkers for predicting exudative conversion in eyes with type 1 nonexudative MNV. For eyes with a high risk of exudative conversion, more frequent follow-up is recommended.