gms | German Medical Science

Advances in OCT angiography (OCTA), in particular elastic registration and averaging of multiple en face OCTA images, has now allowed the choriocapillaris (CC) to be accessed non-invasively. Through these OCTA studies, we have learned that the CC progressively attenuates with age with progressive increase in the area of CC flow deficits, which correspond to the spaces in between capillaries with blood flow. In addition, this age-associated worsening of the CC appears to be more dramatic centrally. Given that AMD, and in particular drusen, tends to impact the central macula, this age-dependent central worsening of the CC may be relevant. Supporting this contention, we observed that the CC flow deficits were more severe/extensive directly under drusen, and in particular below drusen with hyporeflective cores or drusen with overlying hyper-reflective foci --- suggesting that the CC alterations appeared to mirror the overall AMD disease severity. In addition, localized CC flow deficits appeared to predict future enlargement of drusen or the appearance of new isolated drusen, suggesting that the regional distribution of drusen was not stochastic, but rather driven by the underlying choriocapillaris. In addition, CC flow deficits have been observed to surround both CNV and GA lesions, and the severity of flow deficits in eyes with GA appears to predict the rate of progression of enlargement of these GA lesions. Taken together, these observations highlight the critical role of the CC in AMD disease progression and emphasize the role of CC imaging with OCTA as an important biomarker in the assessment of AMD.