Measurement of the Eye's Blood Vessels Using the Dynamic Vessel Analyzer (DVA)

Study Overview
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Brief Summary
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The purpose of this research study is examine the response of the blood vessels in the eye to a light flicker stimulus using the Dynamic Vessel Analyzer (DVA) on two separate days in healthy individuals. The DVA uses an instrument which is used during routine eye examinations. The hypothesis of the study is that the changes in eye's blood vessel will be similar between the two visits; thus establishing reproducibility of the measurements for future comparisons to individuals with stroke or heart disease. In addition, this study will compare the eye's blood vessel responses to responses of the blood vessels in the arm using Doppler ultrasound.

Detailed Description
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Retinal blood vessels have been suggested to be an index of the cerebral and coronary microvasculature function. Since the retinal vessels are not under direct sympathetic control, this vascular bed is an ideal location to examine local mechanisms of vascular regulation(i.e. metabolite/endothelial and myogenic). Based on previously published data on animal and human responses, the central purpose for the proposed research is to compare the retinal and brachial vasodilatation responses in healthy subjects using the Dynamic Vessel Analyzer (DVA). Our rationale for this proposal is to better understand retinal blood flow in healthy individuals, gain insight into vascular reactivity in different vascular beds, and lastly to establish standards and reproducibility of DVA Measurements.

Official Title
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Reproducibility of Dynamic Vessel Analyzer Measurements and Establishment of Standards

Conditions
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Healthy

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy Individuals Age: 21 to 65 years Non-smokers Non-obese Exclusion Criteria: History of cardiovascular, pulmonary, peripheral vascular disease, renal, prostate, and urinary retention disease; Hypertension; Narrow angle Glaucoma or Age Related Macular Degeneration. Pregnancy Inability to fixate using eye device Does not wish to participate

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 65 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Healthy Subjects<br>Healthy participants between the ages of 21 and 65 years old. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To characterize changes in the diameter of retinal blood vessels to a light-induced flicker stimulus in healthy subjects on two separate visits. |  | 1 Year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To compare retinal vasodilator responses to brachial reactive hyperemic responses. |  | 1 Year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Vasodilation, Vessel Reactivity, Dynamic Vessel Analyzer, Retina