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Effect of Oxygen Breathing on Flicker Induced Blood Flow Changes in the Optic Nerve Head

This study has been completed.
Information provided by:
Medical University of Vienna Identifier:
First received: November 30, 2006
Last updated: December 1, 2006
Last verified: November 2006

Background It has recently 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 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 an decrease in pO2 in the tissue. Thus, in this study we set out to investigate the flicker light induced increase in blood flow under elevated blood pO2.

Study rationale The motive for the investigation of retinal blood flow regulation is to enhance our understanding of the coupling mechanism between increased neural activity and blood flow in the retina in order to gain new insight in the pathophysiology of several eye diseases associated with ocular vascular disorders Study objectives To test the hypothesis whether oxygen breathing influences flicker light induced changes in optic nerve head blood flow

Condition Intervention
Healthy Drug: breathing 100% oxygen

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Diagnostic

Resource links provided by NLM:

Further study details as provided by Medical University of Vienna:

Primary Outcome Measures:
  • Retinal vessel diameters

Study Start Date: December 2002
Estimated Study Completion Date: December 2003

Ages Eligible for Study:   19 Years and older   (Adult, Senior)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • healthy volunteers

Exclusion Criteria:

  • Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study
  • Treatment in the previous 3 weeks with any drug
  • Symptoms of a clinically relevant illness in the 3 weeks before the first study day
  • Blood donation during the previous 3 weeks
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Please refer to this study by its identifier: NCT00406224

Sponsors and Collaborators
Medical University of Vienna
Principal Investigator: Gerhard Garhofer, MD Medical University of Vienna
  More Information Identifier: NCT00406224     History of Changes
Other Study ID Numbers: FliOxyGen
Study First Received: November 30, 2006
Last Updated: December 1, 2006 processed this record on June 23, 2017