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

The recruitment status of this study is unknown because the information has not been verified recently.

Verified June 2009 by Medical University of Vienna.
Recruitment status was Not yet recruiting

Sponsor:

Information provided by:

Medical University of Vienna

ClinicalTrials.gov Identifier:

NCT00915226

First received: June 3, 2009

Last updated: June 4, 2009

Last verified: June 2009

History of Changes

Tracking Information

First Received Date ^ICMJE

June 3, 2009

Last Updated Date

June 4, 2009

Start Date ^ICMJE

September 2009

Estimated Primary Completion Date

June 2010 (final data collection date for primary outcome measure)

Current Primary Outcome Measures ^ICMJE

Ocular perfusion pressure - ONH blood flow relationship [ Time Frame: 9 months ] [ Designated as safety issue: No ]

Original Primary Outcome Measures ^ICMJE

Same as current

Change History

Complete list of historical versions of study NCT00915226 on ClinicalTrials.gov Archive Site

Current Secondary Outcome Measures ^ICMJE

Not Provided

Original Secondary Outcome Measures ^ICMJE

Not Provided

Current Other Outcome Measures ^ICMJE

Not Provided

Original Other Outcome Measures ^ICMJE

Not Provided

Descriptive Information

Brief Title ^ICMJE

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

Official Title ^ICMJE

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

Brief Summary

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 an increased evidence, that vascular dysregulation plays a role in the development of glaucomatous damage.

Detailed Description

Not Provided

Study Type ^ICMJE

Interventional

Study Phase

Not Provided

Study Design ^ICMJE

Allocation: Non-Randomized
Intervention Model: Crossover Assignment
Masking: Open Label
Primary Purpose: Basic Science

Condition ^ICMJE

Healthy

Intervention ^ICMJE

Procedure: Suction cup application
The IOP will be raised by an 11 mm diameter, standardized suction cup placed on the temporal sclera with the anterior edge at least 1 mm from the limbus.
Procedure: Squatting
Squatting

Study Arm (s)

Not Provided

Publications *

Not Provided

* Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.

Recruitment Information

Recruitment Status ^ICMJE

Not yet recruiting

Estimated Enrollment ^ICMJE

Estimated Completion Date

October 2010

Estimated Primary Completion Date

June 2010 (final data collection date for primary outcome measure)

Eligibility Criteria ^ICMJE

Inclusion Criteria:

Men aged between 19 and 35 years, nonsmokers
Body mass index between 15th and 85th percentile (Must et al. 1991)
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

Gender

Male

Ages

19 Years to 35 Years

Accepts Healthy Volunteers

Yes

Contacts ^ICMJE

Contact: Gerhard Garhöfer, MD

+43140400 ext 2981

gerhard.garhoefer@meduniwien.ac.at

Location Countries ^ICMJE

Austria

Administrative Information

NCT Number ^ICMJE

NCT00915226

Other Study ID Numbers ^ICMJE

OPHT-310505-2

Has Data Monitoring Committee

Not Provided

Responsible Party

Elzbieta Polska, MD, Department of Clinical Pharmacology, Medical University of Vienna

Study Sponsor ^ICMJE

Medical University of Vienna

Collaborators ^ICMJE

Not Provided

Investigators ^ICMJE

Study Director:

Elzbieta Polska, MD

Department of Clinical Pharmacology, Medical University of Vienna

Information Provided By

Medical University of Vienna

Verification Date

June 2009

^ICMJE Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP

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