OCT angiography-derived biomarkers of retinal and choroidal microvascular changes in dry age-related macular...

This study aimed to identify optical coherence tomography angiography (OCTA) biomarkers associated with disease severity in dry age-related macular degeneration (dAMD). This cross-sectional study included 142 eyes (104 patients) with dAMD, classified as early (n = 34), intermediate (n = 40), or late stage (n = 37) according to the Beckman Classification, and 30 control eyes without AMD. OCTA-images were obtained using the ZEISS PLEX Elite 9000, vascular metrics such as vessel density, total number of junctions, total and average vessel length, junction density, total number of endpoints, and lacunarity were assessed in the superficial capillary plexus, deep capillary plexus (DCP), and choriocapillaris (CC) using AngioTool software. The CC showed the most pronounced changes, with vessel percentage area reduced from 58.98 ± 4.86% in controls to 52.14 ± 10.30% in intermediate and 31.34 ± 11.27% in late AMD (P <.001). Total vessel length declined from 407.52 ± 16.33 mm to 367.09 ± 49.18 mm and 217.23 ± 86.88 mm, respectively (P <.001), while lacunarity increased nearly 50-fold in late AMD (0.56 ± 0.91 vs 0.01 ± 0.00; P <.001). In the DCP, vessel percentage area decreased from 45.68 ± 4.92% in controls to 41.95 ± 5.08% in intermediate and 38.24 ± 6.71% in late AMD (P <.001). Vessel length dropped from 275.21 ± 21.82 mm to 254.13 ± 28.78 mm and 224.68 ± 36.37 mm (P <.001), with increased lacunarity in intermediate and late stages (P <.01). The superficial capillary plexus showed early alterations, with vessel percentage area reduced from 41.46 ± 1.58% in controls to 39.42 ± 3.45% in early AMD (P = .017) and total vessel length decreased from 202.85 ± 10.65 mm to 191.42 ± 18.67 mm and 185.92 ± 18.09 mm in intermediate AMD (P <.001). Mean lacunarity was elevated in all AMD stages (P <.001). OCTA reveals distinct, layer-specific microvascular changes in AMD mainly within DCP and CC. Vessel percentage area, total vessel length, and lacunarity represent sensitive, noninvasive OCTA biomarkers of microvascular impairment in dry AMD, with potential applicability for longitudinal disease monitoring and as quantitative imaging endpoints in future interventional trials.