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Sponsored by: |
Medical University of Vienna |
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Information provided by: | Medical University of Vienna |
ClinicalTrials.gov Identifier: | NCT00719342 |
It has been shown that diffuse luminance flicker increases retinal and optic nerve head blood flow. This indicates that a neuro-vascular coupling between neural activity and blood flow exists in the retina as described previously for the brain. Although a lot of mediators such as NO, pO2, pCO2, H+ and K+ have been proposed, the mechanism of this coupling is still a matter of controversy. However, it has been shown in an animal experiment, that an increase in blood flow, evoked by diffuse luminance flicker stimulation is paralleled by decrease in pO2 in the tissue. In a recently performed study we could show that breathing of 100% O2 did not influence flicker induced changes in the retina and optic nerve head. However, breathing of 100% oxygen also leads to a pronounced vasoconstriction of the retinal vessels and in turn to a increased tension of the vessel wall. Recent evidence indicates that a combination of 92% O2 and 8% CO2 can, at least partially, counteract the vasoconstrictory effect of O2 and increases tissue pO2. Thus, in this study the investigators set out to investigate the flicker light induced increase in blood flow under a mixture of O2/CO2 .
Condition | Intervention |
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Flicker-Induced Vasodilatation |
Drug: Oxygen + Carbondioxide Other: full field flickering light at 12.5 Hz |
Study Type: | Interventional |
Study Design: | Basic Science, Randomized, Double Blind (Subject, Investigator), Placebo Control, Crossover Assignment, Safety/Efficacy Study |
Official Title: | Effect of Breathing a Mixture of 92% O2 + 8% CO2 on Flicker Induced Blood Flow Changes in Ocular Perfusion |
Estimated Enrollment: | 24 |
Study Start Date: | June 2008 |
Estimated Study Completion Date: | August 2009 |
Estimated Primary Completion Date: | August 2009 (Final data collection date for primary outcome measure) |
Ages Eligible for Study: | 18 Years to 35 Years |
Genders Eligible for Study: | Both |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
Exclusion Criteria:
Contact: Gerhard Garhöfer, MD | +43 40400 ext 2981 | gerhard.garhoefer@meduniwien.ac.at |
Austria | |
Department of Clinical Pharmacology, Medical University of Vienna | Not yet recruiting |
Vienna, Austria, 1090 | |
Department of Clinical Pharmacology, Medical University of Vienna | Recruiting |
Vienna, Austria, 1090 |
Principal Investigator: | Michael Wolzt, MD | Department of Clinical Pharmacology, Medical University of Vienna |
Responsible Party: | Department of Clinical Pharmacology, Medical University of Vienna ( Gerhard Garhöfer, MD ) |
Study ID Numbers: | OPHT-030606 |
Study First Received: | July 1, 2008 |
Last Updated: | December 18, 2008 |
ClinicalTrials.gov Identifier: | NCT00719342 |
Health Authority: | Austria: Agency for Health and Food Safety |
Retinal vessel diameter Flicker-induced vasodilatation Optic nerve head blood flow Ocular Physiology Regional Blood Flow |