Correlation of drusen burden and vascular integrity in age-related macular degeneration using three-dimensional choroidal vascular model.

PURPOSE: To study intricate relationship between drusen volume and evolving dynamics of retinal and choroidal vasculature in dry age-related macular degeneration (AMD).

METHODS

Patients underwent swept-source optical coherence tomography angiography (SS-OCTA) using Plex Elite 9000 device. Retinal thickness, retinal vessel perfusion, drusen volume, choroidal thickness (ChT), choroidal vascularity index (CVI), choroidal vessel diameters (MChVD), and intervessel distance (IVD) were assessed. The Advanced Research and Innovation (ARI) Network, ResUNet model, and Phansalkar thresholding were utilized for image analysis. The linear mixing model was used for the statistical analysis.

RESULTS

We assessed 53 eyes from 40 patients with dry AMD (22 eyes with early-stage, 31 eyes with intermediate-stage eyes). The mean age was 75.25 years and 62.5% were females. The mean LogMar visual acuity was 0.09 ± 0.17 standard deviation (SD) in early-stage and 0.19 ± 0.14 SD in intermediate-stage (p = 0.03). Mean drusen volume was 0.075 ± 0.125 SD mm3 in early-stage and 0.24 ± 0.26 SD mm3 in intermediate-stage (p = 0.005). Mean ChT was thicker, and mean CVI was higher in the early-stage compared to the intermediate-stage (p < 0.05). A decrease of 11.48 μm in MChVD for every 1 mm³ increase in drusen volume was noted.

CONCLUSION

With increase in drusen volume, a reduction in CVI and MChVD was noted, without any significant association with changes in retinal metrics, suggesting that choroidal vessels may exhibit early changes during disease progression.