Ocular Blood Flow in Early Glaucoma Patients Before and After Treatment With Dorzolamide

• Status: Unknown status
• Trial end date: 2006-06-01
• Target enrollment: 0
• Participant gender: All

Summary

Impaired ocular blood flow is an important risk factor in the pathogenesis of primary open angle glaucoma (POAG). A few studies suggest that topical dorzolamide 2% may increase optic nerve perfusion. The objectives of this study are to learn the effects of dorzolamide on the retinal and optic nerve blood flow of glaucoma patients.

The present study is a prospective, randomized, double-masked, crossover design study of newly diagnosed or already treated patients with early glaucoma.

The investigators will check ocular blood flow parameters using the Canon Laser Blood Flowmeter (CLBF), used to evaluate retinal arteriole blood flow, and the Heidelberg retinal flowmeter (HRF), which measures blood flow through capillary beds in the retina and optic nerve head.

Any demonstrated improvements to retinal and optic nerve blood flow with dorzolamide, will mean that the drug may protect against ischaemic nerve and retinal damage. Any documented improvement in flow could lead to a major change in the management of glaucoma patients as well as other retinal ischemic diseases such as diabetic retinopathy and central retinal vein occlusion.

• Phase: N/A
• Accepts Healthy Volunteers?: No

Details

• Lead Sponsor: University Health Network, Toronto
• Collaborator: Merck Frosst Canada Ltd.
• Treatments: Dorzolamide

Criteria

Inclusion Criteria:

1. Males or females 20-80 years of age.

2. Presence of typical early glaucomatous optic disc changes (cup/disc ratio ≤ 0.75) and/or early glaucomatous visual field defects (mean deviation less than 5dB and outside of 10° from fixation) in the study eye at the baseline visit.

3. Best corrected visual acuity of at least 20/40.

4. Signed informed consent from the subject

5. The subject should be able to understand the instructions and perform the HRF and CLBF tests as well as be willing and able to comply with the study schedule and treatment.

Exclusion Criteria:

1. Pregnant women or nursing mothers.

2. Any other active ocular disease (ocular infections, Uveitis, etc.)

3. Known allergy or sensitivity to the study medications.

4. Functionally significant visual field loss (mean deviation greater than 5dB) or cup/disc ratio greater than 0.75 or evidence of progressive visual field loss within the last 6 months.

5. Required chronic use of other ocular or systemic hypotensive medications during the study, other than the study medication (e.g. beta-blockers, Ca-channel blockers)

6. Vascular occlusive disease affecting the ocular circulation such as: diabetic retinopathy, central retinal vein occlusion, central retinal artery occlusion, or non-arteritic ischemic optic neuropathy.

7. Previous intraocular surgery or ocular traumas.

8. Any past history of serious systemic condition affecting cerebral circulation including: hypertension, diabetes, cerebral vascular accident (CVA), or coronary artery bypass graft (CABG).