Direct visualization and characterization of erythrocyte flow in human retinal
capillaries |
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Authors: | Phillip Bedggood Andrew Metha |
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Institution: | Department of Optometry and Vision Sciences, The University of Melbourne, 3010, Australia |
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Abstract: | Imaging the retinal vasculature offers a surrogate view of systemic vascular health, allowing
noninvasive and longitudinal assessment of vascular pathology. The earliest anomalies in vascular
disease arise in the microvasculature, however current imaging methods lack the spatiotemporal
resolution to track blood flow at the capillary level. We report here on novel imaging technology
that allows direct, noninvasive optical imaging of erythrocyte flow in human retinal capillaries.
This was made possible using adaptive optics for high spatial resolution (1.5 μm), sCMOS
camera technology for high temporal resolution (460 fps), and tunable wavebands from a broadband
laser for maximal erythrocyte contrast. Particle image velocimetry on our data sequences was used to
quantify flow. We observed marked spatiotemporal variability in velocity, which ranged from 0.3 to
3.3 mm/s, and changed by up to a factor of 4 in a given capillary during the 130 ms imaging period.
Both mean and standard deviation across the imaged capillary network varied markedly with time, yet
their ratio remained a relatively constant parameter (0.50 ± 0.056). Our observations concur
with previous work using less direct methods, validating this as an investigative tool for the study
of microvascular disease in humans.OCIS codes: (110.1080) Active or adaptive optics, (120.7250) Velocimetry, (170.1470) Blood or tissue constituent monitoring, (170.2655) Functional monitoring and imaging, (170.4470) Ophthalmology |
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