Expired Study
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Hershey, Pennsylvania 17033


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.

Study summary:

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.


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

Study is Available At:

Original ID:




Secondary ID:

IRB # 29113

Study Acronym:

Brief Title:

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

Official Title:

Reproducibility of Dynamic Vessel Analyzer Measurements and Establishment of Standards

Overall Status:


Study Phase:




Minimum Age:

21 Years

Maximum Age:

65 Years

Quick Facts

Healthy Volunteers
Oversight Has DMC
Study Is FDA Regulated
Study Is Section 801
Has Expanded Access

Study Source:

Penn State University

Oversight Authority:

United States: Institutional Review Board

Reasons Why Stopped:

Study Type:


Study Design:

Observational Model: Case-Only, Time Perspective:

Number of Arms:


Number of Groups:


Total Enrollment:


Enrollment Type:


Overall Contact Information

Official Name:Kerstin Bettermann, MD, PhD
Principal Investigator
Penn State College of Medicine

Study Dates

Start Date:October 2008
Completion Date:December 2011
Completion Type:Actual
Primary Completion Date:December 2011
Primary Completion Type:Actual
Verification Date:February 2012
Last Changed Date:February 6, 2012
First Received Date:October 30, 2008

Study Outcomes

Outcome Type:Secondary Outcome
Measure:To compare retinal vasodilator responses to brachial reactive hyperemic responses.
Time Frame:1 Year
Safety Issues:False
Outcome Type:Primary Outcome
Measure:To characterize changes in the diameter of retinal blood vessels to a light-induced flicker stimulus in healthy subjects on two separate visits.
Time Frame:1 Year
Safety Issues:False

Study Interventions

There are no available Study Interventions

Study Arms

Study Arm Type:Other
Arm Name:Healthy Subjects
Description:Healthy participants between the ages of 21 and 65 years old.

Study Agencies

Agency Class:Other
Agency Type:Lead Sponsor
Agency Name:Penn State University

Samples and Retentions

Study Population: Healthy Subjects
Sample Method:Non-Probability Sample

Study References

There are no available Study References

Data Source: ClinicalTrials.gov

Date Processed: January 21, 2020

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