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A Comparison of the Effect of Dorzolamide and Timolol on Optic Disk Blood Flow in Patients With Open Angle Glaucoma

This study has been completed.
Information provided by:
Medical University of Vienna Identifier:
First received: October 7, 2009
Last updated: NA
Last verified: October 2009
History: No changes posted

Glaucoma is one of the most common causes of blindness in the industrialized nations. For a long time glaucoma has been defined as a disease in which high intraocular pressure (IOP) leads to irreversible optic disk damage and concommitant visual field loss. However, recent investigations show that IOP is not necessarily an adequate measure of clinical severity or a predictor of clinical progression: about 20% of all eyes with high IOP do not develop visual field loss and some patients suffering from visual field loss due to optic disk damage have normal IOP. Hence, factors other than IOP are likely involved in the pathogenesis of glaucoma. The role of vascular factors in the pathogenesis of glaucoma has recently received much attention and optic nerve head hypoperfusion may play a critical role in the development of glaucoma. It may therefore be important for an optimal prevention of visual field defects in glaucoma that the topical antiglaucoma drugs used do not only reduce IOP but also stabilize or enhance the perfusion of the optic nerve head.

Therefore, the aim of the present study is to compare the effect of a 3 months treatment with timolol or dorzolamide in patients with open angle glaucoma on optic disk blood flow.

Condition Intervention Phase
Glaucoma, Open-Angle
Drug: Dorzolamide 2%
Drug: Timolol 0.5%
Phase 2
Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Basic Science
Official Title: A Double-masked Comparison of the Effect of Dorzolamide and Timolol on Optic Disk Blood Flow in Patients With Open Angle Glaucoma

Resource links provided by NLM:

Further study details as provided by Medical University of Vienna:

Primary Outcome Measures:
  • Percent change over baseline after 3 months of treatment of optic disk blood flow measured with the Heidelberg Retina Flowmeter [ Time Frame: 5 minutes measurement of optic disk blood flow on 3 study days ]
  • Percent change over baseline after 3 months of treatment of fundus pulsation amplitude (FPA) in the optic disk as assessed with laser interferometry [ Time Frame: 5 minutes measurement of FPA on 3 study days ]

Enrollment: 160
Study Start Date: May 1999
Study Completion Date: December 2003
Primary Completion Date: December 2001 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: 1
Patients with open angle glaucoma
Drug: Dorzolamide 2%
Active Comparator: 2
Patients with open angle glaucoma
Drug: Timolol 0.5%


Ages Eligible for Study:   19 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Men and women older than 19 years
  • Primary open angle glaucoma or ocular hypertension with IOP higher than 22 mmHg in at least one eye
  • Washout period for previous antiglaucoma treatment: two weeks for adrenergic agonists, one week for parasympathomimetic agents

Exclusion Criteria:

  • Exfoliation glaucoma, pigmentary glaucoma
  • History of acute angle closure
  • Intraocular surgery or argon laser trabeculoplasty within the last 6 months
  • Ocular inflammation or infection within the last 3 months
  • Contact lenses
  • Patients with bradycardia (heart rate less than 50 beats/min)
  • Second or third degree heart block
  • Asthma
  • COPD
  • Congestive Heart Failure
  • Severe renal impairment (Creatinine clearance less than 1.8 l/h
  • History or hypersensitivity to one of the study drugs or drugs with similar chemical structure
  • History of non-IOP responder to beta-blockers or carbonic anhydrase inhibitors
  • Pregnancy
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Please refer to this study by its identifier: NCT00991822

Department of Clinical Pharmacology, Medical University of Vienna
Vienna, Austria, 1090
Sponsors and Collaborators
Medical University of Vienna
Principal Investigator: Hans G Eichler, MD, Prof. Medical University of Vienna
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: HG Eichler, MD, Prof, Department of Clinical Pharmacology, Medical University of Vienna Identifier: NCT00991822     History of Changes
Other Study ID Numbers: OPHT-200198
Study First Received: October 7, 2009
Last Updated: October 7, 2009

Keywords provided by Medical University of Vienna:
open angle glaucoma

Additional relevant MeSH terms:
Glaucoma, Open-Angle
Ocular Hypertension
Eye Diseases
Adrenergic beta-Antagonists
Adrenergic Antagonists
Adrenergic Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Physiological Effects of Drugs
Anti-Arrhythmia Agents
Antihypertensive Agents
Carbonic Anhydrase Inhibitors
Enzyme Inhibitors processed this record on May 25, 2017