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

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.

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Key information

Conditions

Glaucoma Eye Diseases Ocular Hypertension

Age range

40 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Massachusetts Eye and Ear Infirmary

Boston, Massachusetts, 02114, United States

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Dorzolamide 2%-timolol 0.5%

Drug

BID OU for 6 weeks

Other names: Cosopt, RVD intervention after run-in on timolol 0.5% bid OU

Brimonidine 0.2%-0.5% timolol 0.5

Drug

BID OU for 6 weeks

Other names: Combigan, RVD intervention after run-in on timolol 0.5% bid OU

Primary outcomes

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.

Sponsors and collaborators

Lead sponsor

Massachusetts Eye and Ear Infirmary

Other

Registry information

Important dates

Study start: 2009
Primary completion: 2012
Study completion: 2012
First posted: Jan 19, 2009
Registry last updated: Apr 4, 2017

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Published trials that share one or more normalized conditions with this study.

Completed