Optic Nerve Head Autoregulation During Changes in Arterial Blood Pressure

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01663883
Recruitment Status : Completed
First Posted : August 13, 2012
Last Update Posted : August 13, 2012
Information provided by (Responsible Party):
Gerhard Garhofer, Medical University of Vienna

Brief Summary:

Constant despite changes in perfusion pressure. It is observed in many vascular beds of the human body to prevent that variations in perfusion pressure are directly transmitted into changes in blood flow. This is necessary to prevent ischemia and/or hypoxia during decreased blood flow and bleeding or increased capillary pressure during increased blood flow.

In the eye, several studies have reported that retinal blood flow is autoregulated over a wide range of ocular perfusion pressures. Unfortunately only few data are available for the optic nerve head. To gain data about autoregulation is of special importance given that several important ocular diseases such as glaucoma and age-related macular degeneration are associated with impaired autoregulation. In humans most data were collected using laser Doppler flowmetry.

The present study aims to investigate the phenomenon of transient reduction in blood flow and to gain insight in the regulatory mechanisms of optic nerve head blood flow during isometric exercise.

Condition or disease Intervention/treatment Phase
Decreased Vascular Flow Other: Isometric exercise Not Applicable

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 40 participants
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Study Start Date : February 2012
Actual Primary Completion Date : April 2012
Actual Study Completion Date : August 2012

Arm Intervention/treatment
Experimental: Healthy subjects Other: Isometric exercise
use of a handgrip for 3x2 minutes

Primary Outcome Measures :
  1. Optic nerve head blood flow [ Time Frame: 12 minutes ]

Secondary Outcome Measures :
  1. Systolic/diastolic blood pressure [ Time Frame: 14 minutes ]
  2. Intraocular pressure [ Time Frame: at baseline and minute 13 ]
  3. Pulse rate [ Time Frame: 14 minutes ]

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Ages Eligible for Study:   18 Years to 35 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Men and women aged between 18 and 35 years, nonsmokers
  • Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
  • Normal ophthalmic findings, ametropia less than 3 diopters

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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01663883

Department of Clinical Pharmacology
Vienna, Austria, 1090
Sponsors and Collaborators
Medical University of Vienna
Principal Investigator: Gerhard Garhöfer, MD Department of Clinical Pharmacology, Medical University of Vienna

Responsible Party: Gerhard Garhofer, Ass. Prof. Priv. Doz. Dr., Medical University of Vienna Identifier: NCT01663883     History of Changes
Other Study ID Numbers: OPHT-210911
First Posted: August 13, 2012    Key Record Dates
Last Update Posted: August 13, 2012
Last Verified: August 2012

Keywords provided by Gerhard Garhofer, Medical University of Vienna:
Blood flow autoregulation
optic nerve head blood flow
isometric exercise
ocular physiology