Fig. 4

Shadowing in AMD. a–f Signal attenuation from drusen can be misinterpreted as non-perfusion in the choriocapillaris. Careful examination of the corresponding structural OCTA scan can rectify this error. a, d 6 x 6 mm choriocapillaris slab of a patient with AMD. a White arrow points to an area of apparent flow reduction. b Corresponding structural choriocapillaris slab. White arrow shows that the same area has reduced signal intensity. c B-scan shows a druse at this location. Signal reduction in this area should not be interpreted as non-perfusion, as it is likely due to signal attenuation and not flow reduction. d Identical choriocapillaris slab as that shown in panel A. White arrow points to an area of apparent flow reduction. e Corresponding structural choriocapillaris slab shows that this area has appropriate signal intensity (white arrow). f B-scan shows no druse or underlying pathology in this area. Signal reduction in this area can be appropriately interpreted as choriocapillaris loss