The Effect of Topical Brimonidine on the Ocular Hemodynamics in Patients of POAG Using OCTA

July 23, 2022 updated by: Ahmed Mohamed Mohamed Ameen Ismail, Fayoum University

The Effect of Topical Brimonidine on the Hemodynamics of the Optic Nerve Head and Retinochoroidal Circulation in Patients of Primary Open Angle Glaucoma Using Optical Coherence Tomography Angiography

Topical Brimonidine is a well-established topical antigalucoma, ocular hypotensive therapeutic that has been in use since 1996. Brimonidine stands out among other topical ocular hypotensives in that it has a neuroprotective effect that is independent of IOP reduction. This has been demonstrated in multiple animal and human controlled studies both in vivo and in vitro. The mechanisms proposed so far to account for this neuroprotection focus mainly on molecular level antiapoptotic effects and modulation of some excitatory stimuli like glutamate. In this study we try to test the hypothesis that a positive hemodynamic profile of Brimonidine on ocular blood flow may be responsible at least in part for its unique neuroprotective effects.

Study Overview

Detailed Description

  • Study Design: A prospective, longitudinal, interventional, uncontrolled study
  • Participants: primary open angle glaucoma patients recruited during the period of study from the fayoum university hospital ophthalmic outpatient clinic.
  • Methods:

Primary open angle glaucoma patients that are Brimonidine naiive and at the same time either medication naiive or have been on a fixed antiglaucoma medication for at least a month prior will be commenced on Brimonidine 0.2% bid with prior baseline imaging by OCT angiography (Optovue) of macula 6*6 mm and ONH 4.5*4.5 mm. After commencing Brimonidine patients will be followed up by OCT angiography at three visits assigned for 1,2,3 months after commencing Brimonidine. Every time the patient is imaged by OCT, imaging is done twice, once in a seated position at presentation and another- also in a seated position-, but after a protocol of right recumbency for 30 minutes in order to produce a postural position change as a vascular stress test to assess autoregulatory capacity of ocular and systemic circulation.

At each visit, IOP and arterial blood pressure are measured both in the seated position and after the 30-minute recumbency protocol in order to mathematically calculate the mean ocular perfusion pressure that will be correlated with OCT angiography data including vascular density, as well as indirect parameters of blood flow.

Data will be statistically analysed using the SPSS software.

Study Type

Interventional

Enrollment (Actual)

41

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

      • Fayoum, Egypt
        • Fayoum University Hospitals

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

23 years to 83 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Primary open angle glaucoma patients.
  • Brimonidine naiive.
  • Medication naiive or on a fixed antiglaucoma medication for at least a month prior to commencing Brimonidine.

Exclusion Criteria:

  • Glaucomas other than primary open angle glaucoma.
  • Other comorbid diseses both ocular and systemic that might confound the density and flow measurements ( hypertension, diabetes, vasculitis, MacTel, Uveitis)
  • Comorbid diseases that constitute relative or absolute contraindication to Brimonidine ( pregnancy, lactation, bronchial asthma, cardiovascular diseases)
  • Prior use of Brimonidine.
  • A change in the glaucoma medication regimen within Less than one month at time of presentation.
  • Allergy to Brimonidine or related compounds.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Topical Brimonidine 0.2% bid ophthalmic solution
Topical Brimonidine tartrate 0.2% ophthalmic solution used twice daily. It is a selective alpha 2 adrenergic agonist that is used as an ocular hypotensive in glaucoma and ocular hypertension patients and has proposed neuroprotective effect.
Topical Brimonidine tartrate 0.2% bid ophthalmic solution. A selective alpha 2 adrenergic agonist with ocular hypotensive and neuroprotective properties used in glaucoma and ocular hypertension.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in macular and peripapillary vascular densities
Time Frame: At baseline before Brimonidine and 1,2,3 months thereafter.
The vascular density measured by optical coherence tomography angiography represents the percentage area of flow-positive regions compared to the whole imaged area. Measured densities include (superficial and deep vascular densities) both of the macular area as well as radial peripapillary capillary density of the parapapillary area.
At baseline before Brimonidine and 1,2,3 months thereafter.
Change in macular and peripapillary flow indices
Time Frame: At baseline before Brimonidine and 1,2,3 months thereafter.
An arbitrary flow index will be indirectly calculated using the density data of optical coherence tomography angiography, intraocular pressure and arterial blood pressure measurements.
At baseline before Brimonidine and 1,2,3 months thereafter.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in intraocular pressure
Time Frame: At baseline before Brimonidine and 1,2,3 months thereafter.
Comparing intraocular pressure measurements at baseline with those on subsequent visits.
At baseline before Brimonidine and 1,2,3 months thereafter.
Change in vascular autoregulatory capacity
Time Frame: At baseline before Brimonidine and 1,2,3 months thereafter.
Assessing both systemic as well as ocular vascular autoregulatory capacity making use of the 30-minute recumbency protocol as a vascular stress test.
At baseline before Brimonidine and 1,2,3 months thereafter.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 1, 2020

Primary Completion (Actual)

December 1, 2021

Study Completion (Actual)

July 1, 2022

Study Registration Dates

First Submitted

January 30, 2022

First Submitted That Met QC Criteria

July 23, 2022

First Posted (Actual)

July 26, 2022

Study Record Updates

Last Update Posted (Actual)

July 26, 2022

Last Update Submitted That Met QC Criteria

July 23, 2022

Last Verified

July 1, 2022

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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