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Effect of Cosopt Versus Combigan on Retinal Vascular Autoregulation in Primary Open Angle Glaucoma (POAG)

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ClinicalTrials.gov Identifier: NCT00824824
Recruitment Status : Completed
First Posted : January 19, 2009
Results First Posted : October 28, 2016
Last Update Posted : April 4, 2017
Sponsor:
Information provided by (Responsible Party):

Study Description
Brief Summary:

We have completed a study in which we examined the response of the retinal circulation to changes in posture from sitting to lying down in patients with primary open angle glaucoma (POAG). This alteration in position produces changes in the local blood pressure at the entrance to the retinal vasculature. In a healthy retina, the vasculature adapts by dilating and constricting in order to maintain a steady blood flow rate. In an eye with POAG, this often does not occur. As a result, there are large fluctuations in blood flow which may produce the retinal neuronal damage associated with glaucoma.

The purpose of this study is to demonstrate that topical anti-glaucoma treatments with agents that have vasoactive as well as IOP-lowering effects can have a beneficial effect on maintaining a steady retinal blood flow rate even when there are changes in local blood pressure.


Condition or disease Intervention/treatment
Glaucoma Drug: Dorzolamide 2%-timolol 0.5% Drug: Brimonidine 0.2%-0.5% timolol 0.5

Study Design

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 21 participants
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Basic Science
Official Title: Effect of Cosopt Versus Combigan on Retinal Vascular Autoregulation in Primary Open Angle Glaucoma (POAG)
Study Start Date : January 2009
Primary Completion Date : August 2012
Study Completion Date : August 2012


Arms and Interventions

Arm Intervention/treatment
Experimental: Brimonidine 0.2%-timolol 0.5% arm
Patients using timolol were switched to brimonidine tartrate / timolol maleate 0.2%/05% 1 get BID OU for six weeks.
Drug: Brimonidine 0.2%-0.5% timolol 0.5
BID OU for 6 weeks
Other Names:
  • Combigan
  • RVD intervention after run-in on timolol 0.5% bid OU
Active Comparator: Dorzolamide 2%-timolol 0.5% arm
Patients using timolol were switched ti dorzolamide hydrochloride / timolol 0.5% 2%/0.5% bid OU for six weeks
Drug: Dorzolamide 2%-timolol 0.5%
BID OU for 6 weeks
Other Names:
  • Cosopt
  • RVD intervention after run-in on timolol 0.5% bid OU


Outcome Measures

Primary Outcome Measures :
  1. Presence of Retinal Vascular Dysregulation (RVD) [ Time Frame: 6 weeks post treatment ]
    We determined whether RVD was present in the following way. The difference between the retinal blood flow measured while reclining for 30 minutes and the baseline retinal blood flow measured while seated was calculated. In a previous study, we found that among healthy subjects the change in the blood flow while reclining compared to baseline was +6.5% ± 12%. For this study, we defined the normal range of blood flow autoregulation as ± 2 standard deviations about the mean percentage change found in the control group in the initial study (6.5% ± 24.0%); that is, as -17.5% to +30.5%. Participants with a change in retinal blood flow induced by posture change outside this range were randomized to either dorzolamide-timolol fixed combination BID OU or brimonidine-timolol fixed combination BID OU for 6 weeks.


Eligibility Criteria

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Ages Eligible for Study:   40 Years to 80 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • POAG
  • Age 40 to 80 years
  • Untreated IOP greater than 21 mm Hg

Exclusion Criteria:

  • More than two IOP lowering medications
  • Exfoliation or pigment dispersion syndrome
  • Diabetic retinopathy
  • History of ocular surgery
Contacts and Locations

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 ClinicalTrials.gov identifier (NCT number): NCT00824824


Locations
United States, Massachusetts
Massachusetts Eye and Ear Infirmary
Boston, Massachusetts, United States, 02114
Sponsors and Collaborators
Massachusetts Eye and Ear Infirmary
Investigators
Principal Investigator: Louis Pasquale Mass Eye and Ear Infirmary
More Information

Publications:
Responsible Party: Louis Pasquale, MD, Director, Glaucoma Service Associate Director, Telemedicine, Massachusetts Eye and Ear Infirmary
ClinicalTrials.gov Identifier: NCT00824824     History of Changes
Other Study ID Numbers: 08-12-057
First Posted: January 19, 2009    Key Record Dates
Results First Posted: October 28, 2016
Last Update Posted: April 4, 2017
Last Verified: March 2017
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

Keywords provided by Louis Pasquale, MD, Massachusetts Eye and Ear Infirmary:
Retinal Vascular Autoregulation

Additional relevant MeSH terms:
Glaucoma
Glaucoma, Open-Angle
Ocular Hypertension
Eye Diseases
Timolol
Brimonidine Tartrate, Timolol Maleate Drug Combination
Dorzolamide
Brimonidine Tartrate
Adrenergic beta-Antagonists
Adrenergic Antagonists
Adrenergic Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Physiological Effects of Drugs
Anti-Arrhythmia Agents
Antihypertensive Agents
Adrenergic alpha-2 Receptor Agonists
Adrenergic alpha-Agonists
Adrenergic Agonists
Carbonic Anhydrase Inhibitors
Enzyme Inhibitors