| Retinal venous oxygen saturation increases by flicker light stimulation. | |
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MedLine Citation:
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PMID: 20671271 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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PURPOSE: Luminance flicker stimulation of the photoreceptors is known to increase retinal blood flow. Elevated blood velocity was determined using laser Doppler velocimetry, and increased vascular diameters during flicker were observed by measurements with a retinal vessel analyzer. Oxygen supply may be the target of the regulation of retinal blood flow. Thus, the oxygen saturation (SO(2)) in retinal arterioles and venules was investigated along with their diameters. METHODS: Dual-wavelength (548 nm and 610 nm) fundus images were taken in 19 healthy volunteers (mean age, 26 ± 2.5 years) before (baseline) and during luminance flicker stimulation (12.5 Hz; modulation depth, 1:25). Retinal vessel SO(2) (dual-wavelength optical oximetry) and diameters (central retinal arterial and venous equivalents [CRAE and CRVE]) were determined. RESULTS: CRAEs and CRVEs of 193 ± 20 μm and 228 ± 20 μm at baseline increased statistically significant to a maximum of 202 ± 19 μm (P < 0.0005) and 242 ± 17 μm (P < 0.0005), respectively, under flicker stimulation. Although the arterial SO(2) remained unchanged at 98%-99%, an increase of the venous saturation from 60% ± 5.7% to 64% ± 5.9% (P < 0.0005) was found. CONCLUSIONS: In agreement with earlier investigations, the vessel dilation found here indicates an elevation of retinal blood flow by luminance flicker stimulation. This increase of the flow should meet the enhanced metabolic need of the neural retina under a physiological stimulus. The augmentation of venous oxygenation may indicate a higher capillary oxygen concentration, necessary to provide a sufficient diffusion rate of oxygen from the capillaries to the inner retinal tissue. |
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Authors:
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Martin Hammer; Walthard Vilser; Thomas Riemer; Fanny Liemt; Susanne Jentsch; Jens Dawczynski; Dietrich Schweitzer |
Publication Detail:
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Type: Journal Article Date: 2011-01-05 |
Journal Detail:
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Title: Investigative ophthalmology & visual science Volume: 52 ISSN: 1552-5783 ISO Abbreviation: Invest. Ophthalmol. Vis. Sci. Publication Date: 2011 Jan |
Date Detail:
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Created Date: 2011-01-06 Completed Date: 2011-02-07 Revised Date: 2011-03-04 |
Medline Journal Info:
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Nlm Unique ID: 7703701 Medline TA: Invest Ophthalmol Vis Sci Country: United States |
Other Details:
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Languages: eng Pagination: 274-7 Citation Subset: IM |
Affiliation:
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Department of Ophthalmology, University of Jena, Jena, Germany. martin.hammer@med.uni-jena.de |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Blood Flow Velocity Female Hemoglobins / metabolism Humans Laser-Doppler Flowmetry Male Oximetry Oxygen / metabolism* Photic Stimulation* Regional Blood Flow / radiation effects Retina / radiation effects* Retinal Artery / physiology Retinal Vein / physiology* Vasodilation / physiology |
| Chemical | |
Reg. No./Substance:
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0/Hemoglobins; 7782-44-7/Oxygen |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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