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

Reproducibility of Dynamic Vessel Analyzer Measurements and Establishment of Standards

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 Overview

• Status: Completed
• Conditions: Healthy

Detailed Description

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.

• Study Type: Observational
• Enrollment (Actual): 87

Contacts and Locations

Study Locations

• United States
  • Pennsylvania
    • Hershey, Pennsylvania, United States, 17033
      • Penn State Milton S. Hershey Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Healthy Subjects

Description

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 Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Healthy Subjects; Healthy participants between the ages of 21 and 65 years old.

What is the study measuring?

Primary Outcome Measures

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

Collaborators and Investigators

• Sponsor: Penn State University

Study record dates

Study Major Dates

• Study Start: October 1, 2008
• Primary Completion (Actual): December 1, 2011
• Study Completion (Actual): December 1, 2011

Study Registration Dates

• First Submitted: October 30, 2008
• First Submitted That Met QC Criteria: October 30, 2008
• First Posted (Estimate): October 31, 2008

Study Record Updates

• Last Update Posted (Estimate): February 7, 2012
• Last Update Submitted That Met QC Criteria: February 6, 2012
• Last Verified: February 1, 2012

More Information

Terms related to this study

• Keywords: Retina; Vasodilation; Dynamic Vessel Analyzer; Vessel Reactivity
• Other Study ID Numbers: HMC29113; IRB # 29113