Choriocapillaris flow in two different patterns of exudative type 1 macular neovascularization

Background: To compare the characteristics of type 1 macular neovascularization (MNV) and the surrounding choriocapillaris (CC) perfusion in patients with neovascular age-related macular degeneration (nAMD) versus those with pachychoroid neovasculopathy (PNV) using swept-source optical coherence tomography angiography (SS-OCTA). Methods: This retrospective study included 64 treatment-naïve eyes (37 nAMD, 27 PNV) with type 1 MNV. SS-OCTA images were analysed to measure MNV area and perimeter, and CC flow deficits (FD) in five concentric rings surrounding the lesion. CC FD percentage (FD%), area (FDa), and number (FDn) were quantified. Intervortex anastomoses presence was also assessed. Results: MNV lesions in nAMD were significantly larger in area (2.94 vs 1.56 mm², p= 0.013) and perimeter (8.76 vs 5.85 mm, p= 0.004) compared to PNV. PNV eyes showed higher FD% and larger FDa across all rings (p< 0.05), while FDn did not differ significantly. Intervortex anastomoses were more prevalent in PNV (81.5% vs 35.1%, p= 0.0002). In nAMD, MNV size correlated positively with FD% in inner rings and FDn in all rings. In PNV, MNV size correlated only with FDn. Conclusions: Despite smaller MNV lesions, PNV eyes demonstrated more extensive CC flow deficits compared to nAMD. The distinct CC flow patterns and their correlations with MNV characteristics suggest different pathophysiological mechanisms underlying these conditions. These findings may have implications for differential diagnosis and tailored treatment approaches in nAMD and PNV.