Effect of Systemic Hypoxia and Hyperoxia on Retinal Oxygen Saturation

Study Overview
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Brief Summary
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Adequate perfusion and oxygenation is essential for the function of the inner retina. Although it is known that oxygen tension is very well autoregulated in the retina, the physiological mechanisms behind this regulation process are not fully explored. The development of new instruments for the non-invasive measurement of oxygen tension in retinal vessels now allows for the more precise investigation of these physiological processes. The current study seeks to evaluate the retinal oxygen saturation in healthy subjects while breathing different oxygen mixtures to achieve a hypoxic and a hyperoxic state.

Official Title
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Effect of Systemic Hypoxia and Hyperoxia on Retinal Oxygen Saturation

Conditions
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Retinal Blood Flow, Retinal Oxygenation

Intervention / Treatment
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* Drug: 100% oxygen breathing
* Drug: 15% oxygen in N2 breathing
* Drug: 12% oxygen in N2 breathing


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men and women aged between 18 and 35 years Nonsmokers 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, ametropy < 3 Dpt. Exclusion Criteria: Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study (except oral contraceptive) Symptoms of a clinically relevant illness in the 3 weeks before the first study day Presence of any form of anemia Blood donation during the previous 3 weeks Pregnancy

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 100% oxygen breathing<br> | Drug: 100% oxygen breathing<br>* 100% oxygen breathing - 30 minutes<br>|
| Experimental: 15% oxygen in N2 breathing<br> | Drug: 15% oxygen in N2 breathing<br>* 15% oxygen in N2 breathing - 30 minutes<br>|
| Experimental: 12% oxygen in N2 breathing<br> | Drug: 12% oxygen in N2 breathing<br>* 12% oxygen in N2 breathing - 30 minutes<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Retinal oxygen saturation |  | On the study day - during each breathing period (6 times) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Retinal blood flow |  | On the study day - during each breathing period (6 times) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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retinal oxygen saturation, retinal blood flow, hyperoxia, hypoxia