Identification of OCTA Biomarkers and Cutoff Values Associated with Disease Severity in Dry Age-Related Macular...

Optical coherence tomography angiography (OCTA) enables noninvasive assessment of retinal and choroidal microvasculature and may provide quantitative biomarkers of disease severity in dry age-related macular degeneration (AMD). This study aimed to identify OCTA-derived vascular parameters associated with consecutive stages of dry AMD and determine cutoff values for stage differentiation.

This cross-sectional study included 182 eyes of 123 participants. Eyes were classified according to the Beckman classification into control, early, intermediate, and late dry AMD groups. OCTA imaging was performed using the ZEISS PLEX Elite 9000 swept-source OCTA system. Quantitative analysis of the superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillaris (CC) was conducted using AngioTool software. Vessel density, vessel length, junction-related parameters, endpoints, and lacunarity were analyzed. Group comparisons were performed using analysis of variance (ANOVA) or the Kruskal-Wallis test with post hoc analysis. Receiver operating characteristic (ROC) curves were used to evaluate diagnostic performance and determine optimal cutoff values.

In the SCP, vessel density decreased from 43.83 ± 2.08% in controls to 41.27 ± 3.96% in intermediate AMD (p < 0.001), and mean lacunarity increased from 0.05 ± 0.01 to 0.07 ± 0.03 (p < 0.001), while other parameters showed no significant differences. In the DCP, vessel density declined from 51.71 ± 2.38% in controls to 48.73 ± 4.66% and 43.80 ± 4.98% across disease stages (p < 0.001), with total vessel length decreasing from 73.32 ± 2.72 to 61.58 ± 6.69 (p < 0.001), indicating progressive vascular simplification. The most pronounced changes were observed in the choriocapillaris, where vessel density decreased from 63.28 ± 0.94 to 60.31 ± 1.83% and 26.62 ± 22.30% (p < 0.001), and total vessel length from 102.80 ± 2.24 to 35.68 ± 38.42 (p < 0.001). ROC analysis identified SCP mean lacunarity (cutoff 0.0575, AUC 0.76) as a marker of early disease. In the DCP, total number of junctions below 254 and total vessel length below 66.10 were associated with advanced disease. The highest diagnostic performance was observed for choriocapillaris parameters, including vessel density below 57.38 and total vessel length below 91.10, with sensitivity exceeding 94% and specificity above 80%.

OCTA-derived microvascular parameters demonstrate layer-specific alterations in dry AMD. Mean lacunarity in the SCP appeared to be the most sensitive marker of early changes, whereas reductions in junction density and total vessel length in the DCP reflected progressive vascular simplification. The strongest association with disease severity was observed in the choriocapillaris, particularly for vessel density and total vessel length. The identified cutoff values for DCP and CC parameters were associated with different stages of dry AMD and may support stage differentiation and quantitative assessment of disease severity in clinical settings.