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Pieter Jan Frederik Nelis, Nicole Eter; Angioanalytics at work: Decrease of the retinal blood flow density with increasing age. Invest. Ophthalmol. Vis. Sci. 2016;57(12):4626.
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© ARVO (1962-2015); The Authors (2016-present)
Quantitative analysis of the retinal vasculature, visualized with optical coherence tomography angiography (OCTA), gives us the possibility to non-invasively measure the flow density (FD; flow per volume in percentage) in the superficial and deep layers of the retina. In a retrospective, observational clinical study in healthy subjects, we tested the hypothesis that with an increase in age a decrease of FD in the different retinal layers of the parafoveal region would be observed.
45 eyes of 32 healthy subjects (mean age 50,42 +/- 18,08) without systemic or ocular pathology were included and examined using the OCTA with the split-spectrum amplitude-decorrelation angiography algorithm (RTVue XR Avanti with AngioVue; Optovue Inc, Fremont, California, USA). FD was determined in the superficial and deep layers of the retinal vasculature, using the module Angioanalytics (Beta SW; Optovue Inc, Fremont, California, USA). As a quality parameter, the signal strength index (SSI) was determined. Statistical analysis was performed in SPSS Version 22 (IBM) to evaluate possible correlations.
A strong negative correlation between age and the FD in the parafoveal area of the superficial (r = -0,596, p < 0,001) and deep retinal vasculature (r = -0,535, p < 0,001) was observed. The scatter plot showed a decrease in FD after the age of 60 years old. Also, the correlation between age and the SSI was strongly negative. The scatter plot of this correlation showed already in the 40-60 age period a decrease of SSI, which went further down after the age of 60 years old. A correlation between age and the FD in the foveal area of the superficial (r = 0,049, p = 0,749) and deep (r = 0,161, p = 0,291) vasculature could not be shown.
Our results suggest that with an increase of age a decrease of FD in the different retinal layers of the parafoveal region occurs. Considering that the decrease of FD in the parafoveal region is observed at a later age than the decrease of image quality, it is unlikely that the observed decrease of FD would be a mere imaging side effect due to an evolving cataract. Nevertheless, further research is necessary to evaluate the effect of the ocular media on the OCTA images and to determine other factors, influencing the FD in the retinal vasculature.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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