Effects of Vitamin C on Hyperoxia-Induced Reduction of Retinal Blood Flow
Not Applicable
Completed
- Conditions
- Ocular PhysiologyRegional Blood Flow
- Registration Number
- NCT00712907
- Lead Sponsor
- Medical University of Vienna
- Brief Summary
High arterial blood oxygen tension leads to vasoconstriction of retinal vessels, possibly related to an interaction between reactive oxygen species and endothelium-derived vasoactive factors. Vitamin C is a potent antioxidant capable of reversing endothelial dysfunction due to increased oxidant stress. Vitamin C appears to have vasodilatory properties, but the underlying mechanisms are not well understood.
In the present study we hypothesized that hyperoxic vasoconstriction of retinal vessels could be diminished by vitamin C.
Ocular blood flow will be determined by non-invasive methods, including laser Doppler velocimetry and the Zeiss retinal vessel analyser.
- Detailed Description
Not available
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- Male
- Target Recruitment
- 12
Inclusion Criteria
- Men aged between 19 and 35 years, nonsmokers
- Body mass index between 15th and 85th percentile (Must A 1991)
- Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
- Normal laboratory values unless the investigator considers an abnormality to be clinically irrelevant
- Normal ophthalmic findings, ametropia < 3 Dpt.
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
- History of hypersensitivity to the trial drug or to drugs with a similar chemical structure
- History or presence of gastrointestinal, liver or kidney disease, or other conditions known to interfere with, distribution, metabolism or excretion of study drugs
- Blood donation during the previous 3 weeks
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- CROSSOVER
- Primary Outcome Measures
Name Time Method Intraocular pressure (applanation tonometry) in total 10 minutes Retinal blood flow velocity (laser Doppler velocimetry) in total 6 hours Retinal arterial and venous diameter (Zeiss retinal vessel analyzer) in total 6 hours
- Secondary Outcome Measures
Name Time Method
Trial Locations
- Locations (1)
Department of Clinical Pharmacology
🇦🇹Vienna, Austria
Department of Clinical Pharmacology🇦🇹Vienna, Austria