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

NCT00912665 | Completed DMC

• 1 other identifier: OPHT-150808
• Study Type: interventional
• Target: 40
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Healthy

Keywords

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

Outcome Measures

Primary Outcomes (1)

• Optic nerve head pressure-flow relationship

  in total 3x on 2 study days

Study Arms (1)

Healthy Volunteer

EXPERIMENTAL

Device: Laser Doppler Flowmetry; Device: Goldmann applanation tonometer; Other: squatting; Device: Suction cup

Interventions

Laser Doppler Flowmetry DEVICE

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

Healthy Volunteer

Goldmann applanation tonometer DEVICE

intraocular pressure measurements

Healthy Volunteer

squatting OTHER

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

Healthy Volunteer

Suction cup DEVICE

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

Healthy Volunteer

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Medical University of Vienna: lead

Study Sites (1)

Department of Clinical Pharmacology, Medical University of Vienna

Vienna, Vienna, 1090, Austria

Location

MeSH Terms

Interventions

Laser-Doppler Flowmetry

Intervention Hierarchy (Ancestors)

Diagnostic Techniques, Cardiovascular; Diagnostic Techniques and Procedures; Diagnosis; Rheology; Investigative Techniques

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Ass.Prof.Priv.Doz.Dr.

Study Record Dates

• First Submitted: June 1, 2009
• First Posted: June 3, 2009
• Study Start: July 1, 2009
• Primary Completion: December 1, 2010
• Study Completion: December 1, 2010
• Last Updated: August 10, 2012

Record last verified: 2012-08

Locations

AU (1)