Retinal Function in Relation to Transient or Chronic Challenges to Retinal Metabolism

Study Overview
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Brief Summary
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The aim of the study is to investigate how the retina adapts to different metabolic challenges, e.g. chronic systemic hypoxia, hyperglycemia, special training conditions or diets as well as transient changes in the content of oxygen and glucose in the blood.

Official Title
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Retinal Function in Relation to Transient or Chronic Challenges to Retinal Metabolism

Conditions
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Healthy Individuals, Patients With Diabetes.

Intervention / Treatment
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* Other: Hyperoxia
* Other: Glucose


Participation Criteria
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Eligibility Criteria
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Healthy individuals Inclusion Criteria: Healthy volunteers. No known systemic or ocular disease. Exclusion Criteria: Any systemic or ocular disease. Patients with diabetes Inclusion criteria: Diabetes mellitus No intraocular disease other than conditions attributable to diabetes. Exclusion criteria: Intraocular disease other than conditions attributable to diabetes. Systemic conditions which might contraindicate hyperoxic stimulation.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 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

Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Healthy<br>Healthy study participanats | Other: Hyperoxia<br> <br> * Other names: Hyperoxia is achieved by short-term pure oxygen breathing.;Other: Glucose<br> <br> * Other names: Standardised oral glucose load.;|
| Experimental: Diabetes<br>Patients with diabetes | Other: Hyperoxia<br> <br> * Other names: Hyperoxia is achieved by short-term pure oxygen breathing.;Other: Glucose<br> <br> * Other names: Standardised oral glucose load.;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Retinal vessel diameters during hyperoxia | Measurement of retinal vessel diameters before, during and after hyperoxic stimulation. | Before hyperoxia, after 15 minutes of hyperoxia, 30 minutes after ending hyperoxia | 
| Retinal perfusion velocities during hyperoxia | Measurement of retinal perfusion velocities before, during and after hyperoxic stimulation. | Before hyperoxia, after 15 minutes of hyperoxia, 30 minutes after ending hyperoxia | 
| Retinal oximetry during hyperoxia | Measurement of retinal oximetry status before, during and after hyperoxic stimulation. | Before hyperoxia, after 15 minutes of hyperoxia, 30 minutes after ending hyperoxia | 
| Retinal vessel diameters during hyperglycemia | Measurement of retinal vessel diameters before, during and after hyperglycemic stimulation. | Before glucose ingestion, every 30 minutes for 3 hours following oral glucose load | 
| Retinal perfusion during hyperglycemia | Measurement of retinal perfusion velocities before, during and after hyperglycemic stimulation. | Before glucose ingestion, every 30 minutes for 3 hours following oral glucose load | 
| Retinal oximetry during hyperglycemia | Measurement of retinal oximetry status before, during and after hyperglycemic stimulation. | Before glucose ingestion, every 30 minutes for 3 hours following oral glucose load |