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Clinical Trial Details — Status: Withdrawn

Administrative data

• NCT number: NCT00915226
• Other study ID #: OPHT-310505-2
• Status: Withdrawn
• Phase: N/A
• First received: June 3, 2009
• Last updated: November 13, 2014
• Start date: September 2009
• Est. completion date: October 2010

Study information

• Verified date: November 2014
• 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 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.

Recruitment information / eligibility

• Status: Withdrawn
• Enrollment: 0
• Est. completion date: October 2010
• Est. primary completion date: June 2010
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Male
• Age group: 19 Years to 35 Years

Eligibility

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

Study Design

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

Related Conditions & MeSH terms

• Healthy

Intervention

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.
• Squatting
Squatting

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	Ocular perfusion pressure - ONH blood flow relationship		9 months	No