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Abstract #9170 Published in IGR 5-2
Choroidal blood flow during exercise-induced changes in the ocular perfusion pressure
Lovasik JV; Kergoat H; Riva CE; Petrig BL; Geiser MInvestigative Ophthalmology and Visual Science 2003; 44: 2126-2132
PURPOSE: The high metabolic rate of the human retina is supported by the choroidal vasculature. Knowledge of the normal choroidal blood flow (ChBF) responses to various physiological stimuli is therefore highly important if the pathophysiology of ocular diseases involving the choroid is to be understood better. In the present study, the hemodynamic responses of the subfoveal ChBF were examined during and after an exercise-induced increase in the ocular perfusion pressure (OPP). METHODS: Twenty-six healthy volunteers, 19 to 55 years of age, participated in this two-phase study. Each subject increased resting OPP through stationary biking at a heart rate (HR) of 140 beats per minute (bpm) over 20 minutes. The ChBF was measured by laser Doppler flowmetry (LDF), the systemic BP by electronic sphygmomanometry, and the resting intraocular pressure (IOP) by applanation tonometry. RESULTS: OPP increased by approximately 43% at the onset of biking, and then decreased biphasically to approximately 12% above resting value by the end of biking. ChBF remained within 10% of its basal value throughout biking. Immediately after biking, OPP decreased twice as much as ChBF in the same time frame. CONCLUSIONS: The dissociation between OPP and ChBF during biking and recovery suggests that some mechanism keeps ChBF close to its basal value, an observation that indicates blood flow regulation.
Dr. J.V. Lovasik, School of Optometry, University of Montreal, Montreal, Quebec, Canada. john.vincent.lovasik@umontreal.ca
Classification:
6.11 Bloodflow measurements (Part of: 6 Clinical examination methods)