Evaluation of flicker induced hyperemia in the retina and optic nerve head measured by Laser Speckle Flowgraphy

• Published in: PloS one Vol. 13; no. 11; p. e0207525
• Main Authors: Fondi, Klemens, Bata, Ahmed M., Luft, Nikolaus, Witkowska, Katarzyna J., Werkmeister, René M., Schmidl, Doreen, Bolz, Matthias, Schmetterer, Leopold, Garhöfer, Gerhard
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 28.11.2018; Public Library of Science (PLoS)
• Subjects: Adult; Arteries; Biology and Life Sciences; Biomedical engineering; Blood; Blood circulation; Blood flow; Blood Flow Velocity; Blood vessels; Coupling; Development and progression; Engineering and Technology; Eye diseases; Female; Flicker; Flow velocity; Glaucoma; Head; Health physics; Hemodynamics; Humans; Hyperemia; Hyperemia - diagnostic imaging; Hyperemia - physiopathology; Instruments (Equipment); Kepler, Johannes; Laser speckle; Laser-Doppler Flowmetry; Lasers; Male; Medical imaging; Medicine and Health Sciences; Methods; Optic nerve; Optic Nerve - blood supply; Optic Nerve - diagnostic imaging; Optic Nerve - physiopathology; Optical tomography; Pharmacology; Photic Stimulation; Physical Sciences; Physiology; Retina; Retina - diagnostic imaging; Retina - physiopathology; Retinal Artery - diagnostic imaging; Retinal Artery - physiopathology; Risk factors; Stimulation; Veins; Visual stimuli; Austria; Singapore
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0207525

The coupling between neural activity and blood flow is a physiological key principle of ocular blood flow regulation. The current study was performed to investigate whether Laser speckle flowgraphy (LSFG), a commercially available technique for measuring blood flow, is capable to assess flicker-induced haemodynamic changes in the retinal and optic nerve head (ONH) circulation. Twenty healthy subjects were included in this cross sectional study. A commercial LSFG instrument was used to measure blood flow at the ONH as well as in retinal vessels before and during stimulation with flickering light. Mean blur rate (MBR), a measure of relative blood flow velocity, was obtained for the ONH and relative flow volume (RFV) a measure of relative blood flow of the respective retinal vessels. Stimulation with flicker light increased ONH MBR by +17.5%±6.6% (p<0.01). In retinal arteries, flicker stimulation led an increase of +23.8±10.0% (p<0.05) in total RFV. For retinal veins, an increase of +23.1%±11.0 (p<0.05) in total RFV was observed during stimulation. A higher response was observed in nasal RFV compared to temporal RFV in retinal arteries (nasal: +28.9%±20.0%; temporal: +20.4%±17.6%, p<0.05) and veins (nasal: +28.3%±19.6%; temporal +17.8%±18.9%, p<0.05). As shown previously with other techniques, flicker stimulation leads to an increase in retinal and optic nerve head blood flow. Our results indicate that LSFG is an appropriate method for the quantification of retinal and ONH blood flow during visual stimulation and may be used as a non-invasive, easy to use tool to assess neuro-vascular coupling in humans.