Quantitative analysis of choroidal parameters of intermediate and neovascular age-related macular degeneration using ultra-widefield swept-source OCTA.

PURPOSE: To evaluate wide-field choroidal alterations in intermediate AMD (iAMD) and neovascular AMD (nAMD) using ultra-widefield swept-source optical coherence tomography angiography (UWF SS-OCTA).

METHODS

This cross-sectional study included 40 iAMD eyes, 81 nAMD eyes, and 68 age-matched normal eyes. Eight choroidal parameters-thickness (ChT), volume (CV), vascularity index (CVI), vascular volume/area (CVV/a), stromal volume/area (CSV/a), stromal index (CSI), choriocapillaris density (CCD), and large choroidal vessel density (LCVD)-were measured across nine subfields using 24 × 20 mm scans. Generalized estimating equations (GEE) and receiver operating characteristic (ROC) analysis were used. Subgroup analyses evaluated the effects of treatment status and macular neovascularization (MNV) type within nAMD.

RESULTS

Baseline demographics were comparable across groups (all P > 0.05). Compared with normal eyes, nAMD eyes showed lower ChT in 8/9 subfields and lower CV in 7/9; compared with iAMD eyes, both were lower in 3/9 (all Bonferroni-corrected pairwise P < 0.05). CSI was higher than normal in 5/9 subfields for both iAMD and nAMD, with no significant iAMD-nAMD differences in any subfield. For distinguishing nAMD from controls, central ChT had the highest diagnostic accuracy (AUC = 0.894), followed by CV (AUC = 0.883) and CSV/a (AUC = 0.840). Only CSV/a differed by treatment status; no Bonferroni-corrected pairwise differences were detected among MNV subtypes.

CONCLUSION

nAMD showed broader ChT and CV reductions, whereas higher CSI was confined to selected subfields in both AMD groups, without significant iAMD-nAMD differences. These findings indicate distinct stage-associated choroidal patterns. Central ChT showed the strongest discrimination between nAMD and normal eyes.