Regulation of Optic Nerve Head Blood Flow During Combined Changes in Intraocular Pressure and Arterial Blood Pressure

December 5, 2014 updated by: Medical University of Vienna

Regulation of Optic Nerve Head Blood Flow During Combined Changes in Intraocular Pressure and Arterial Blood Pressure.

Autoregulation is the ability of a vascular bed to maintain blood flow despite changes in perfusion pressure. The existence of an effective autoregulation in the optic nerve head (ONH) circulation has been shown in animals and humans. Moderate elevation of intraocular pressure (IOP) caused only slight effect on ONH blood flow in monkeys, cats and rabbits. In humans, during an artificial IOP rise using a suction cup method the ONH blood flow maintains almost constant until IOP reaches 40-55 mmHg. During isometric exercise the upper limit of autoregulation appears to be approximately 40% above the baseline ocular perfusion pressure. The mechanism behind ONH blood flow autoregulation is still unknown. The present experiments are designed to improve the investigators' knowledge of the physiology of regulatory mechanisms in ONH circulation, which may be helpful for a better understanding of blood flow abnormalities in glaucoma. This is of importance, because there is increasing evidence that vascular dysregulation plays a role in the development of glaucomatous damage.

Study Overview

Status

Withdrawn

Conditions

Intervention / Treatment

Study Type

Interventional

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

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

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

19 years to 35 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

Male

Description

Inclusion Criteria:

  • Men aged between 19 and 35 years, nonsmokers
  • Body mass index between 15th and 85th percentile
  • Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
  • Normal ophthalmic findings, ametropia < 1 Dpt

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
  • Symptoms of a clinically relevant illness in the 3 weeks before the first study day
  • Blood donation during the previous 3 weeks
  • Presence of intraocular pathology: ocular hypertension, glaucoma, retinal vasculopathy or other retinal diseases

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Non-Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Ocular perfusion pressure - ONH blood flow relationship
Time Frame: 9 months
9 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Medical University of Vienna

Investigators

  • Study Director: Elzbieta Polska, MD, Department of Clinical Pharmacology, Medical University of Vienna

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

July 1, 2009

Primary Completion (Actual)

December 1, 2010

Study Completion (Actual)

December 1, 2010

Study Registration Dates

First Submitted

June 3, 2009

First Submitted That Met QC Criteria

June 4, 2009

First Posted (Estimate)

June 5, 2009

Study Record Updates

Last Update Posted (Estimate)

December 8, 2014

Last Update Submitted That Met QC Criteria

December 5, 2014

Last Verified

November 1, 2014

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • OPHT-310505

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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