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

NCT00914992 · Status: WITHDRAWN · Phase: NA · Type: INTERVENTIONAL

Last updated 2014-12-08

No results posted yet for this study

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 increasing evidence that vascular dysregulation plays a role in the development of glaucomatous damage.

Conditions

  • Healthy

Interventions

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.

OTHER

Squatting

Squatting

Sponsors & Collaborators

  • Medical University of Vienna

    lead OTHER

Principal Investigators

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

Study Design

Allocation
NON_RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Model
CROSSOVER

Eligibility

Min Age
19 Years
Max Age
35 Years
Sex
MALE
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2009-07-31
Primary Completion
2010-12-31
Completion
2010-12-31

Countries

  • Austria

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT00914992 on ClinicalTrials.gov