Retinal Pigment Epithelial Abnormality and Choroidal Large Vascular Flow Imbalance Are Associated with Choriocapillaris Flow Deficits in Age-Related Macular Degeneration in Fellow Eyes

Abstract

Choriocapillaris flow deficits detected on optical coherence tomography angiographs were retrospectively analyzed. In 38 age-related macular degeneration (AMD) fellow eyes, without fundus findings (26 men, 71.7 ± 1.9 years old), and 22 control eyes (11 men, 69.4 ± 1.8), the choriocapillaris flow area (CCFA) ratio and coefficient of variation (CV) of the CCFA ratio (which represented the heterogeneity of the ratio), negatively and positively correlated with age (all p < 0.01), respectively. Moreover, the respective mean values were lower (p = 0.0031) and greater (p = 0.002) in AMD fellow eyes than in the control eyes. The high-risk condition of AMD fellow eyes was defined by a CCFA ratio <58.5%, and the CV of the CCFA ratio ≥0.165 (odds ratio (OR), 5.408; 95% confidence interval (CI): 1.117–21.118, p = 0.035, after adjusting for age and sex) was related to the presence of fundus autofluorescence abnormality (OR, 16.440; 95% CI, 1.262–214.240; p = 0.033) and asymmetrically dilated choroidal large vasculature (OR, 4.176; 95% CI, 1.057–16.503; p = 0.042), after adjusting for age and sex. The presence of fundus autofluorescence abnormality indicated a retinal pigment epithelium (RPE) abnormality. The RPE volume was reduced in the latter eye group, particularly in the thinner choroidal vasculature. In addition to aging, RPE abnormality and choroidal large vascular flow imbalances were associated with exacerbated heterogeneous choriocapillaris flow deficits in AMD fellow eyes without macular neovascularization.

Diabetic choriocapillaris flow deficits affect the outer retina and are related to hemoglobin A1c and systolic blood pressure levels

“…According to one post-mortem study, capillary dropout in the choriocapillaris of patients with diabetes is due to an increased number of polymorphonuclear leukocytes in the vascular lumen 23 . Heterogeneity of the choriocapillaris flow were similar to the changes which we reported in the fellow eyes of patients with unilateral age-related macular degeneration 16 , 17 , wherein low-grade chronic inflammation is known to be involved in the pathogenesis 24 , 25 . Diabetes is a chronic inflammatory disease 26 , and the heterogeneous progression of flow deficits may most likely reflect disease progression in response to systemic inflammatory conditions and not to focal stimuli.…”

“…2a). The flow signal areas in the choriocapillaris slab (CCFAs) were evaluated after binarization based on the Phansalkar local binarization threshold as reported previously 16 , 17 , 43 . The CCFAs were calculated using ImageJ (National Institutes of Health, Bethesda, MD, USA; available at http://rsb.info.nih.gov/ij/index.html ) 44 .…”

“…The CV of the CCFA ratio was evaluated to assess the homogeneity or heterogeneity of choriocapillaris flow as we have previously reported 16 , 17 . The binarized images were split into 18 × 18 smaller images, and the CCFA ratio of each small image was calculated to evaluate the standard deviation and then divided by average.…”

“…In this study, OCT and OCTA images of the macular area of patients with diabetes who had not yet experienced substantial visual loss, and were thus assumed not to have severe macular changes, were analyzed. The OCTA images were used to evaluate choriocapillaris flow as per the Phansalkar binarization method and to measure the choriocapillaris flow area (CCFA) ratio 16 , 17 . The variation in the CCFA ratio according to various locations in the analyzed area was represented in terms of the coefficient of variation (CV) of the CCFA ratio 16 , 17 .…”

“…The OCTA images were used to evaluate choriocapillaris flow as per the Phansalkar binarization method and to measure the choriocapillaris flow area (CCFA) ratio 16 , 17 . The variation in the CCFA ratio according to various locations in the analyzed area was represented in terms of the coefficient of variation (CV) of the CCFA ratio 16 , 17 . The influence of the diabetic choriocapillaris change on the outer retinal layer; the photoreceptors and the RPE, were evaluated in OCT images.…”