Longitudinal Choriocapillaris and Retinal Vascular Flow Changes on OCTA with Progression to Advanced AMD

To evaluate retinal and choriocapillaris (CC) vascular flow changes on optical coherence tomography angiography (OCTA) associated with progression of intermediate age-related macular degeneration (iAMD) to geographic atrophy (GA) or neovascular AMD (nAMD).

This retrospective, longitudinal cohort study included 68 eyes from 50 patients with iAMD at baseline who underwent OCTA and clinical examination at baseline and at 24 months. Quantitative analysis of CC flow deficits (FDs) and superficial capillary plexus vessel density (VD) was performed at baseline and after 24 months by comparing eyes that progressed to GA or nAMD to eyes that remained stable.

Over 24 months, 7 eyes (10.3%) developed GA and 9 eyes (13.2%) developed nAMD, including 2 that progressed to both. Eyes that developed GA had significantly greater CC FD total area at baseline when compared with stable iAMD eyes (p=0.013) and developed significant decrease in parafoveal VD (p=0.026) and full macular VD (p=0.019) after GA onset. In contrast, eyes that developed nAMD showed no significant OCTA differences at baseline when compared to stable iAMD eyes but developed a new significant increase in CC FD total area (p=0.044) and FAZ perimeter (p=0.036) after nAMD onset (p=0.044).

In iAMD eyes progressing to GA, CC ischemia was detectable before GA onset, with subsequent retinal VD loss after GA development. In iAMD eyes progressing to nAMD, CC ischemia developed concurrent with neovascularization. OCTA-derived CC and retinal flow metrics may serve as non-invasive biomarkers to stratify iAMD eyes at risk for progression.