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

NCT ID: NCT00912665

Last Updated: 2012-08-10

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

40 participants

Study Classification

INTERVENTIONAL

Study Start Date

2009-07-31

Study Completion Date

2010-12-31

Brief Summary

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Autoregulation is defined as the ability of a vascular bed to adapt its vascular resistance to changes in perfusion pressure. In the eye, several studies have reported that retinal blood flow is autoregulated over a wide range of ocular perfusion pressures. In the optic nerve head only few data are available. Large scale studies have shown that reduced ocular perfusion pressure is an important risk factor for the prevalence, the incidence and the progression of primary open angle glaucoma.

Former studies that investigated ocular blood flow autoregulation only measured choroidal blood flow. For the optic nerve head only few data are available, although it seems likely that it underlies similar autoregulatory mechanisms.

The primary goal of the present study is to gain more insight into these phenomena in humans.

The present study aims to investigate the pressure/flow relationship as a measure for optic nerve head autoregulation during combined changes of intraocular pressure and arterial pressure. Intraocular pressure will be increased by the use of a suction cup technique, mean arterial pressure will be increased by squatting. During the whole procedure, optic nerve head blood flow will be measured continuously.

Detailed Description

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Conditions

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Healthy

Keywords

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Optic Nerve Head Blood Flow Intraocular Pressure Regional Blood Flow Ocular Physiology Optic Disk

Study Design

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Allocation Method

NA

Intervention Model

SINGLE_GROUP

Primary Study Purpose

BASIC_SCIENCE

Blinding Strategy

NONE

Study Groups

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Healthy Volunteer

Group Type EXPERIMENTAL

Laser Doppler Flowmetry

Intervention Type DEVICE

blood flow measurements at the temporal neuroretinal rim to assess optic nerve head blood flow

Goldmann applanation tonometer

Intervention Type DEVICE

intraocular pressure measurements

squatting

Intervention Type OTHER

Subjects will perform squatting for 6 minutes while either blood flow or intraocular pressure measurements

Suction cup

Intervention Type DEVICE

Experimental stepwise increase of intraocular pressure while either optic nerve head blood flow or intraocular pressure measurements

Interventions

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Laser Doppler Flowmetry

blood flow measurements at the temporal neuroretinal rim to assess optic nerve head blood flow

Intervention Type DEVICE

Goldmann applanation tonometer

intraocular pressure measurements

Intervention Type DEVICE

squatting

Subjects will perform squatting for 6 minutes while either blood flow or intraocular pressure measurements

Intervention Type OTHER

Suction cup

Experimental stepwise increase of intraocular pressure while either optic nerve head blood flow or intraocular pressure measurements

Intervention Type DEVICE

Eligibility Criteria

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Inclusion Criteria

* Men and women aged between 18 and 35 years, nonsmokers
* Men and women will be included in equal parts
* Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
* Normal findings in the laboratory testings unless the investigator considers an abnormality to be clinically irrelevant
* Normal ophthalmic findings, ametropia less than 1 diopter

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
Minimum Eligible Age

18 Years

Maximum Eligible Age

35 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Medical University of Vienna

OTHER

Sponsor Role lead

Responsible Party

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Gerhard Garhofer

Ass.Prof.Priv.Doz.Dr.

Responsibility Role PRINCIPAL_INVESTIGATOR

Locations

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Department of Clinical Pharmacology, Medical University of Vienna

Vienna, Vienna, Austria

Site Status

Countries

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Austria

Other Identifiers

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OPHT-150808

Identifier Type: -

Identifier Source: org_study_id