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

Healthy Clinical Trial

Official title:

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00912665
• Other study ID #: OPHT-150808
• Status: Completed
• Phase: N/A
• First received: June 1, 2009
• Last updated: August 9, 2012
• Start date: July 2009
• Est. completion date: December 2010

Study information

• Verified date: August 2012
• Source: Medical University of Vienna
• Contact: n/a
• Is FDA regulated: No
• Health authority: Austria: Agency for Health and Food Safety
• Study type: Interventional

Clinical Trial 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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 40
• Est. completion date: December 2010
• Est. primary completion date: December 2010
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 18 Years to 35 Years

Eligibility

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

Study Design

Endpoint Classification: Safety/Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Basic Science

Related Conditions & MeSH terms

• Healthy

Intervention

Device:
• Laser Doppler Flowmetry
blood flow measurements at the temporal neuroretinal rim to assess optic nerve head blood flow
• Goldmann applanation tonometer
intraocular pressure measurements

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

Device:
• Suction cup
Experimental stepwise increase of intraocular pressure while either optic nerve head blood flow or intraocular pressure measurements

Locations

Country	Name	City	State
Austria	Department of Clinical Pharmacology, Medical University of Vienna	Vienna

Sponsors (1)

Lead Sponsor	Collaborator
Medical University of Vienna

Country where clinical trial is conducted

Austria, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Optic nerve head pressure-flow relationship		in total 3x on 2 study days	No