Retinal Vascular Reactivity in Subjects With Newly Diagnosed Glaucoma Before and After Selective Laser Trabeculoplasty

Overview

The purpose of this study is to assess retinal blood flow and vascular reactivity in patients with newly diagnosed primary open angle glaucoma pre- and post-primary Selective Laser Trabeculoplasty(SLT). Canon Laser Blood Flowmeter will be used for the assessment of retinal blood flow.

Full Title of Study: “Retinal Vascular Reactivity in Response to Isoxic Hypercapnia in Subjects With Newly Diagnosed Glaucoma”

Study Type

  • Study Type: Observational
  • Study Design
    • Time Perspective: Prospective
  • Study Primary Completion Date: November 2011

Detailed Description

We previously found that vascular reactivity improved after short term treatment with dorzolamide drops. It is not clear whether this improvement was a direct effect of the medication or secondary effect of the decrease in IOP. We would like to see the change of vascular reactivity before and after SLT, which will decrease the intraocular pressure without pharmacologic effect.

Interventions

  • Procedure: Selective Laser Trabeculoplasty
    • Patient will have selective laser trabeculoplasty as the first treatment for glaucoma. This treatment will be dictated clinically, since we do not assign the interventions.

Arms, Groups and Cohorts

  • untreated glaucoma patients
    • We will evaluate the blood flow before and after Selective Laser Trabeculoplasty in patients with primary open angel glaucoma.

Clinical Trial Outcome Measures

Primary Measures

  • blood flow
    • Time Frame: before and two-week after SLT
    • The Canon Laser Blood Flowmetry will be used to assess the retinal blood flow.

Secondary Measures

  • Intraocuclar pressure
    • Time Frame: before and two-week after SLT
    • Intraocular pressure (IOP) will be measured by Goldmann applanation tonometry.

Participating in This Clinical Trial

Inclusion Criteria

1. Age 40-75 years (Male or Female) 2. Best corrected visual acuity of at least 20/40 3. No previous treatment for glaucoma 4. Ametropia less than ±6.0 DS and ±2.5 DC) 5. Non-smoker 6. No cardiovascular/respiratory disorders Exclusion Criteria:

1. Past history of diabetes and cerebrovascular accident 2. Vascular occlusive disease affecting the ocular circulation such as: diabetic retinopathy, retinal vein occlusion and retinal artery occlusion 3. Previous intraocular surgery 4. Ocular media opacities limiting the use of the imaging tests

Gender Eligibility: All

Minimum Age: 40 Years

Maximum Age: 75 Years

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • University of Toronto
  • Collaborator
    • University of Western Ontario, Canada
  • Provider of Information About this Clinical Study
    • Dr. Chris Hudson, Department of Ophthalmology and Vision Science
  • Overall Official(s)
    • Chris Hudson, PhD, Principal Investigator, University of Toronto
  • Overall Contact(s)
    • Tien Wong, 416-603-5694, twong@uhnres.utoronto.ca

References

Venkataraman ST, Hudson C, Rachmiel R, Buys YM, Markowitz SN, Fisher JA, Trope GE, Flanagan JG. Retinal arteriolar vascular reactivity in untreated and progressive primary open-angle glaucoma. Invest Ophthalmol Vis Sci. 2010 Apr;51(4):2043-50. doi: 10.1167/iovs.09-3630. Epub 2009 Nov 11.

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