Exploring choriocapillaris under reticular pseudodrusen using OCT-Angiography.

Purpose: To evaluate if choriocapillaris (CC) vessel density and CC decorrelation signal index are compromised in eyes with reticular pseudodrusen (RPD) using optical coherence tomography angiography (OCT-A).

Methods: Decorrelation values in OCT-A CC images of 20 RPD patients were measured in the outer superior and the outer inferior sector of the EDTRS grid and compared to age-matched healthy controls. CC vessel density and CC decorrelation signal index were measured within a 30 μm and a 10 μm OCT-A CC slab. CC data were correlated to number of RPD lesions, predominantly present RPD stage, predominantly present RPD type, retinal area affected by RPD and choroidal thickness (CT).

Results: CC vessel density and CC decorrelation signal index decreased in correlation to advancing age in healthy subjects particularly in subjects older than 60 years (CC vessel density: 30 μm: p=0.0019; 10 μm: p=0.0014; CC decorrelation signal index: 30 μm: p=0.0005; 10 μm: p=0.0003). In the RPD group, CC vessel density (outer superior sector, 10 μm: 98.299) and CC decorrelation signal index (89.07) were significantly reduced compared to controls (99.203, p=0.0002; 98.09, p=0.0010). The number of RPD lesions was correlated to a reduced CC vessel density (30 μm: p=0.0355) but not to changes in CC decorrelation signal index. No correlations were found between CC parameters and either RPD stage, RPD type, size of RPD affected area or CT.

Conclusions: OCT-A reveals a distinct reduction in CC vessel density and CC decorrelation signal index in eyes affected by RPD, which emphasizes the relevance of the CC layer in RPD pathogenesis.