Effects of Vitamin C on Hyperoxia-Induced Reduction of Retinal Blood Flow
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Sponsor
- Medical University of Vienna
- Enrollment
- 12
- Locations
- 2
- Primary Endpoint
- Intraocular pressure (applanation tonometry)
Study Overview
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.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Diagnostic
- Masking
- Double (Participant, Investigator)
Eligibility Criteria
- Ages
- 19 Years to 35 Years (Adult)
- Sex
- Male
- Accepts Healthy Volunteers
- Yes
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
Outcomes
Primary Outcomes
Intraocular pressure (applanation tonometry)
Time Frame: in total 10 minutes
Retinal blood flow velocity (laser Doppler velocimetry)
Time Frame: in total 6 hours
Retinal arterial and venous diameter (Zeiss retinal vessel analyzer)
Time Frame: in total 6 hours
Secondary Outcomes
No secondary outcomes reported