Choriocapillaris flow deficit associated with intraretinal hyperreflective foci in intermediate age-related macular degeneration

To evaluate the choriocapillaris (CC) flow deficit (FD) beneath drusen associated with overlying intraretinal hyperreflective foci (HRF).

Patients with intermediate age-related macular degeneration (AMD) who had structural spectral-domain optical coherence tomography (SD-OCT) and OCT angiography (OCTA) using the Cirrus HD-OCT with AngioPlex software were retrospectively evaluated. A 6 × 6-mm-volume scan was used for the SD-OCT and OCTA. Post-imaging processing steps included generation of drusen map, identification of HRF, and generation of a signal-compensated CC slab prior to binarization and CC FD computation. The CC OCTA image was aligned with the drusen + HRF map to define regions of interest for CC FD measurement. The CC was quantified below drusen with and without overlying HRF and within a 150-μm-wide ring surrounding the drusen (unaffected by potential HRF-related shadowing), and across the entire 6 × 6 macular region.

Fifty-three eyes with intermediate AMD were included, 25 eyes with HRF, and 28 eyes with no HRF. The mean ± SD FD% over the whole 6 × 6 macular region was 41.1 ± 3.4 in eyes with HRF compared with 39.5 ± 3.5 in eyes without HRF (p = 0.001). The mean ± SD CC FD% below drusen with HRF (54.4 ± 9.3) was significantly greater than below drusen without HRF (49.6 ± 9.5; p = 0.001). There was a strong positive correlation between the quantity of HRF and the extent of the CC FD (Pearson correlation = 0.81).

Choriocapillaris flow deficits appear to be more severe in eyes with HRF and in particular directly below HRF. As HRF are thought to represent a higher risk or more advanced feature of intermediate AMD, these findings highlight the relationship between the severity of CC FD and overall severity of AMD.