Optic Nerve Head Autoregulation During Changes in Arterial Blood Pressure

Constant despite changes in perfusion pressure. It is observed in many vascular beds of the human body to prevent that variations in perfusion pressure are directly transmitted into changes in blood flow. This is necessary to prevent ischemia and/or hypoxia during decreased blood flow and bleeding or increased capillary pressure during increased blood flow.

In the eye, several studies have reported that retinal blood flow is autoregulated over a wide range of ocular perfusion pressures. Unfortunately only few data are available for the optic nerve head. To gain data about autoregulation is of special importance given that several important ocular diseases such as glaucoma and age-related macular degeneration are associated with impaired autoregulation. In humans most data were collected using laser Doppler flowmetry.

The present study aims to investigate the phenomenon of transient reduction in blood flow and to gain insight in the regulatory mechanisms of optic nerve head blood flow during isometric exercise.

Study Overview

• Status: Completed
• Conditions: Decreased Vascular Flow
• Intervention / Treatment: Other: Isometric exercise

• Study Type: Interventional
• Enrollment (Actual): 40
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Austria
  • Vienna, Austria, 1090
    • Department of Clinical Pharmacology

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 35 years (ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

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 ophthalmic findings, ametropia less than 3 diopters

Exclusion Criteria:

• Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study
• Treatment in the previous 3 weeks with any drug (except oral contraceptives)
• Symptoms of a clinically relevant illness in the 3 weeks before the first study day
• Blood donation during the previous 3 weeks

Study Plan

How is the study designed?

Design Details

• Primary Purpose: BASIC_SCIENCE
• Allocation: NA
• Interventional Model: SINGLE_GROUP
• Masking: NONE

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Healthy subjects	Other: Isometric exercise; use of a handgrip for 3x2 minutes

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Optic nerve head blood flow	12 minutes

Secondary Outcome Measures

Outcome Measure	Time Frame
Systolic/diastolic blood pressure	14 minutes
Intraocular pressure	at baseline and minute 13
Pulse rate	14 minutes

Collaborators and Investigators

• Sponsor: Medical University of Vienna

Study record dates

Study Major Dates

• Study Start: February 1, 2012
• Primary Completion (Actual): April 1, 2012
• Study Completion (Actual): August 1, 2012

Study Registration Dates

• First Submitted: January 24, 2012
• First Submitted That Met QC Criteria: August 9, 2012
• First Posted (Estimate): August 13, 2012

Study Record Updates

• Last Update Posted (Estimate): August 13, 2012
• Last Update Submitted That Met QC Criteria: August 9, 2012
• Last Verified: August 1, 2012

More Information

Terms related to this study

• Keywords: ocular physiology; Autoregulation; isometric exercise; Blood flow autoregulation; optic nerve head blood flow
• Other Study ID Numbers: OPHT-210911