Clinical trial NCT00914407: Measurement of Retinal Blood Flow, Retinal Oxygenation and Retinal Oxygen Extraction in Healthy Subjects During Normoxia and Systemic Hyperoxia
Official title: Measurement of Retinal Blood Flow, Retinal Oxygenation and Retinal Oxygen Extraction in Healthy Subjects During Normoxia and Systemic Hyperoxia
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Healthy
Normoxia
Systemic Hypoxia
Keywords: Ocular physiology
Lead sponsor: Medical University of Vienna
Sponsor class: OTHER
First posted: 2009-06-05
Enrollment: 48
Sex: ALL
Minimum age (years): 18
Maximum age (years): 35
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: BASIC_SCIENCE

Brief summary: The inner retina is crucially dependent on an adequate retinal blood supply. When the retina becomes ischemic and hypoxic this results in severe vision loss due to retinal neovascularization. Measurement of retinal blood flow and retinal oxygenation is, however, still a difficult task. Information on retinal oxygenation is almost unavailable from human studies. In the present protocol the investigators propose a procedure allowing for the measurement of retinal blood flow, retinal oxygenation and retinal oxygen extraction by combining a number of innovative techniques. Specifically, retinal vessel diameters will be measured with a Retinal Vessel Analyzer, retinal blood velocities with bi-directional laser Doppler velocimetry and retinal oxygenation with spectroscopic evaluation of retinal fundus images. This will allow for the calculation of retinal oxygen extraction, a fundamental parameter of retinal function. Up to now, no data for retinal oxygen extraction are available in the literature.


Eligibility criteria: Inclusion Criteria:

* Men and women aged between 18 and 35 years
* Nonsmokers
* Body mass index between 15th and 85th percentile
* 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 except oral contraceptives
* Symptoms of a clinically relevant illness in the 3 weeks before the first study day
* Blood donation during the previous 3 weeks
* Pregnancy

Primary outcomes:
measure: Retinal blood velocity Retinal vessel diameters Oxygen saturation of retinal vessels Oxygen extraction as calculated from these parameters
timeFrame: 20 min ocular blood flow measurement on 1 study day
Secondary outcomes:
Other outcomes:
Locations:
city: Vienna
country: Austria
facility: Department of Clinical Pharmacology, Medical University of Vienna
Study officials:
References:
citation: Fondi K, Aschinger GC, Bata AM, Wozniak PA, Liao L, Seidel G, Doblhoff-Dier V, Schmidl D, Garhofer G, Werkmeister RM, Schmetterer L. Measurement of Retinal Vascular Caliber From Optical Coherence Tomography Phase Images. Invest Ophthalmol Vis Sci. 2016 Jul 1;57(9):OCT121-9. doi: 10.1167/iovs.15-18476.