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Abstract #15133 Published in IGR 8-4
Chorioretinal vascular oxygen tension changes in response to light flicker
Shakoor A; Blair NP; Mori M; Shahidi MInvestigative Ophthalmology and Visual Science 2006; 47: 4962-4965
See also comment(s) by Alon Harris •
PURPOSE: To investigate oxygen tension (Po2 ) changes in the retinal and choroidal vasculatures in response to visual stimulation by light flicker. METHODS: A previously developed optical section phosphorescence imaging system was used to measure Po2 separately in the retinal veins, arteries, and capillaries and in the choroid before and during light flicker. Imaging was performed in rats during light flicker at frequencies between 0 and 14 Hz. Light flicker-induced changes in the chorioretinal vasculature Po2 and arteriovenous Po2 differences were determined. Retinal arterial and venous Po2 were measured along blood vessels as a function of the distance from the optic nerve head. RESULTS: Retinal arterial Po2 and arteriovenous Po2 differences increased with increasing light flicker at frequencies up to 10 Hz, after which no further increase was observed. Significant increases in retinal arterial Po2 (P = 0.009; n =10) and in retinal capillary Po2 (P = 0.04, n = 10) were measured in response to light flicker at 10 Hz. Retinal arteriovenous Po2 differences during light flicker were significantly greater than differences before light flicker (P = 0.01; n = 10). Retinal arterial Po2 decreased significantly with increased distance from the optic nerve head (P ≤ 0.004), whereas retinal venous Po2 remained relatively unchanged (P ≥ 0.4). CONCLUSIONS: Measurement of changes in the chorioretinal vasculature Po2 can potentially advance the understanding of oxygen dynamics in challenged physiological states and in animal models of human retinal diseases.
Dr. A. Shakoor, Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago (UIC), 1855 West Taylor Street, Chicago, IL 60612, USA
Classification:
6.11 Bloodflow measurements (Part of: 6 Clinical examination methods)
5 Experimental glaucoma; animal models
