Artifactual Flow Signals Within Drusen Detected by OCT Angiography

BACKGROUND AND OBJECTIVE To demonstrate possible flow artifacts when imaging drusen with optical coherence tomography angiography (OCTA). PATIENTS AND METHODS Patients with drusen were enrolled in a prospective OCT study using the Zeiss AngioPlex OCTA instrument (Carl Zeiss Meditec, Dublin, CA). Two kinds of en face slabs were created for visualizing both structure and flow. The first slab followed the contour of Bruch's membrane. The second slab had an inner boundary following the retinal pigment epithelium (RPE) contour and an outer boundary following the contour of Bruch's membrane. The structure and flow signals from within the drusen were compared. RESULTS Eleven eyes of nine patients with age-related macular degeneration and drusen were imaged. In all 11 eyes, an artifactual flow signal was seen on the first slab where it intersected the RPE. This flow signal was a projection artifact from the overlying retinal vessels. The second slab did not show evidence of flow within drusen. CONCLUSION OCTA decorrelation projection artifacts can be misinterpreted as apparent flow within drusen if the slab region includes hyperreflective boundary layers such as the RPE. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:517-522.].