Effects of Common Topical Glaucoma Therapy on Optic Nerve Head Blood Flow Autoregulation During Increased Arterial Blood Pressure and Artificially Elevated Intraocular Pressure in Healthy Humans
Information source: Medical University of Vienna
Information obtained from ClinicalTrials.gov on October 19, 2009
Link to the current ClinicalTrials.gov record.
Condition(s) targeted: Glaucoma; Ocular Physiology; Regional Blood Flow
Intervention: Timolol (drug) (Drug); dorzolamide (drug) (Drug); brimonidine (drug) (Drug); Laser Doppler flowmetry (Device); Goldmann applanation tonometer (Device); Suction cup method (Procedure)
Phase: N/A
Status: Not yet recruiting
Sponsored by: Medical University of Vienna Official(s) and/or principal investigator(s):
Gabriele Fuchsjaeger-Mayrl, MD, Principal Investigator, Affiliation: Department of Clinical Pharmacology
Overall contact:
Gerhard Garhofer, MD, Phone: + 43 1 40400 2981, Email: gerhard.garhoefer@meduniwien.ac.at
Summary
Background
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
circulation has been shown in animals and humans. The exact mechanism behind this
autoregulation is still unknown. The motive for the investigation of optic nerve head (ONH)
blood flow autoregulation is to enhance the understanding of pathologic eye conditions
associated with ocular vascular disorders. To clarify the regulatory mechanisms of ONH
microcirculation is of critical importance to understand the pathophysiology of glaucoma,
because there is evidence that glaucoma is associated with optic nerve head ischemia.
Several studies indicate that a disturbed autoregulation might contribute to glaucomatous
optic neuropathy. Currently, five classes of intraocular pressure (IOP) reducing drugs are
available for topical therapy in patients with glaucoma or elevated intraocular pressure.
These drugs have also vasoactive properties, which may influence both the resting ocular
circulation and the autoregulatory mechanisms of blood flow during changes in ocular
perfusion pressure.
Study objective
To investigate the influence of common topical glaucoma therapy on ONH blood flow regulation
during changes in IOP and systemic arterial blood pressure.
Clinical Details
Official title: Effects of Common Topical Glaucoma Therapy on Optic Nerve Head Blood Flow Autoregulation During Increased Arterial Blood Pressure and Artificially Elevated Intraocular Pressure in Healthy Humans
Study design: Basic Science, Randomized, Double Blind (Subject, Investigator), Active Control, Parallel Assignment, Safety/Efficacy Study
Primary outcome: Ocular perfusion pressure - ONH blood flow relationship
Secondary outcome: Blood pressure, heart rate
Eligibility
Minimum age: 19 Years.
Maximum age: 35 Years.
Gender(s): Both.
Criteria:
Inclusion Criteria:
- Men aged between 19 and 35 years, nonsmokers
- Body mass index between 15th and 85th percentile
- 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
Locations and Contacts
Gerhard Garhofer, MD, Phone: + 43 1 40400 2981, Email: gerhard.garhoefer@meduniwien.ac.at
Department of Clinical Pharmacology, Vienna A-1090, Austria
Additional Information
Starting date: September 2008
Ending date: December 2009
Last updated: July 8, 2008
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