Objective  To observe the signal intensity and homogeneity of subretinal hyperreflective material (SHRM) in neovascular age-related macular degeneration (nAMD) and preliminarily analyze its relationship with macular neovascularization (MNV) morphology. Methods A prospective cross-sectional observational study. Forty-six eyes of 46 treatment-naïve nAMD patients with SHRM who initially visited Zhongshan Ophthalmic Center, Sun Yat-sen University from January 1, 2022 to March 31, 2023 were enrolled. Optical coherence tomography (OCT) examination was performed according to a standardized protocol, and 3D Slicer software was used for three-dimensional reconstruction of SHRM lesions. Signal intensity was represented by the mean gray value (mGV) of the three-dimensional lesion area, and homogeneity was represented by the standard deviation of gray values (GV-SD). OCT angiography (OCTA) was used to scan the 6 mm×6 mm area of the macula. FIJI and Angio Tool software were used to measure MNV vascular network total area, perimeter, maximum and minimum diameters, maximum vessel diameter, vascular component area, total number of vascular network junctions and endpoints, vessel dispersion, and mean lacunarity. The ratio of maximum to minimum diameter of the vascular network, average vessel length, vessel density, and vessel fractal index were calculated. Using the mean mGV of the total sample as the standard, the eyes were divided into low-density SHRM group (20 eyes) and high-density SHRM group (26 eyes); using the mean GV-SD of the total sample as the standard, the eyes were divided into homogeneous SHRM group (29 eyes) and non-homogeneous SHRM group (17 eyes). The morphological characteristics of MNV between groups were compared. Independent samples t-test or Mann-Whitney U test was used for between-group comparisons; a multivariate regression model was established to analyze independent factors affecting SHRM signal characteristics. Results Among the 46 eyes of 46 patients, there were 26 eyes of 26 males (56.52%, 26/46) and 20 eyes of 20 females (43.48%, 20/26). The mean age was (65.61±7.50) years. The average vessel length and vessel dispersion in the high-density SHRM group and low-density SHRM group were (6.88±4.56), (11.30±6.31) mm⁻¹ and 41.30±67.26, 13.22±11.34, respectively. Compared with the low-density SHRM group, the high-density SHRM group had significantly lower average vessel length (t=2.645) and higher vessel dispersion (t=−2.090), with statistically significant differences (P=0.012, 0.046). Compared with the homogeneous SHRM group, the non-homogeneous SHRM group had significantly higher total area (t=−2.338), maximum diameter (t=−3.137), and minimum diameter (t=−2.173), with statistically significant differences (P＜0.05). The total number of vascular network junctions in the non-homogeneous SHRM group and homogeneous SHRM group were (90.71±67.34) and (49.34±41.91), respectively; the non-homogeneous SHRM group had significantly more junctions than the homogeneous SHRM group, with a statistically significant difference (t=−2.286, P=0.032). Multivariate regression analysis showed that average vessel length was an independent factor affecting SHRM intensity (odds ratio=0.819, 95% confidence interval 0.705-0.951, P=0.009); there were no independent vascular indicators affecting SHRM reflectivity homogeneity (P＞0.05). Conclusion In nAMD, compared with low-density SHRM, high-density SHRM has significantly lower average vessel length and higher vessel dispersion; compared with homogeneous SHRM, non-homogeneous SHRM has a larger spatial dimension of the vascular network.

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