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Raymond L. Warner, Alberto de Castro, Lucie Sawides, Kaitlyn Sapoznik, Ting Luo, Stephen Burns; Flicker evoked changes in small retinal vessels. Journal of Vision 2019;19(15):21. doi: https://doi.org/10.1167/19.15.21.
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© ARVO (1962-2015); The Authors (2016-present)
To use the dual-beam Adaptive Optics Scanning Laser Ophthalmoscope (AOSLO) to measure blood flow changes in arterioles, venules, and capillaries in the human retina in response to full-field and local flicker stimulation.
The retina of nine healthy subjects ages 25 to 32 were imaged with the dual-beam AOSLO. Vessels targeted for imaging were interconnected arterioles, venules, and capillaries in the superior parafoveal retina. In experiment 1, parafoveal vessel locations were randomized and were imaged in three sets of three 2-minute sessions: (1) No-flicker, (2) Full-Field Flicker (10 Hz), (3) No flicker again. In experiment 2, 10 images in the temporal superior retina in one subject were collected at 7 locations with a local flicker stimulus at the center.
RBC velocities, diameters, and flow were measurable in all subjects with individual vessels from each subject varying in velocity and pulsatility. Flicker stimulation increased the average flow of RBC's for arteriole, venule, and capillary vessels in all subjects. Average flow increased 29% in arterioles, 25% for venules, and 23% for the capillaries. Local flicker stimuli induced variable increases in velocity relative to the position of the local flicker stimulus.
With the use of the dual channel AOSLO, we can measure changes in blood in parafoveal vessels in the human retina. Understanding how flicker stimuli induce changes in the retinal vasculature is important for understanding both how blood flow is regulated in the healthy eye, and ultimately to better understand how disease disrupts neurovascular regulation.
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