Analyzing Formation and Absorption of Avascular Subretinal Hyperreflective Material in nAMD from OCTA-Based Insights

Abstract

To investigate the formation and absorption of avascular subretinal hyperreflective material (avSHRM) in neovascular age-related macular degeneration (nAMD) based on optical coherence tomography angiography (OCTA) characteristics. Prospective cohort study METHODS: This study included patients with treatment-naïve nAMD and followed up for 3 months. Subjects were classified into avSHRM group and non-avSHRM group based on the presence of avSHRM at baseline. Quantitative OCTA characteristics including explant area, perimeter, vessel area, density, length, junctions, endpoints, lacunarity, maximum vessel caliber, vessel dispersion, and fractal dimension were assessed, three-dimensional volume and optical density ratio (ODR) of avSHRM were measured. Comparison analyses, correlate coefficients and regression models were applied to explore factors associated with avSHRM formation and absorption. 88 eyes from 88 patients (39 females) were enrolled. Compared to non-avSHRM group, avSHRM group exhibit a more intricate vasculature, characterized by higher value of macular neovascularization (MNV) perimeter, vessel area, total vessel length, total number of junctions and total number of endpoints (all P < 0.05), as well as the maximum vessel caliber (P < 0.001). In the multivariate model, which has been adjusted for age, gender, and types of medications, avSHRM absorption was correlated with baseline average vessel length, maximum vessel caliber and avSHRM ODR (standardized β = 0.274, -0.367 and -0.334; P = 0.049, 0.010 and 0.018, respectively), with an adjusted R² of 0.453. Quantitative OCTA measurements can be utilized for assessing the dynamics of avSHRM in nAMD. Patients with more complex vasculature are at a higher risk of avSHRM formation. Average vessel length, maximum vessel diameter and avSHRM ODR play a role in its absorption.