Comparing Effects of Two Fixed Combinations Ophthalmic Solutions on Ocular Blood Flow

Study Overview
=================
Brief Summary
-----------------
A 10 week evaluation, crossover design study including a 3 week washout period between treatments, to determine the effects of Combigan® (fixed combination brimonidine tartrate 0.2%/timolol maleate 0.5%) and Cosopt® (fixed combination dorzolamide hydrochloride-timolol maleate ophthalmic solutions) on ocular blood flow as measured by retrobulbar blood flow.

Conditions
-----------------
Glaucoma

Intervention / Treatment
-----------------
* Drug: fixed combination of brimonidine tartrate 0.2% timolol maleate 0.5% ophthalmic solution
* Drug: fixed combination of dorzolamide hydrochloride timolol maleate ophthalmic solution


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Age: 30 years or older. Primary open-angle glaucoma (POAG) or ocular hypertensive in at least one eye. Best corrected visual acuity at least 20/40 in at least one eye. Exclusion Criteria: History of acute angle-closure or a narrow, occludable anterior chamber angle by gonioscopy. History of chronic or recurrent inflammatory eye diseases (e.g., scleritis, uveitis). History or signs of intraocular trauma. Any abnormality preventing reliable applanation tonometry. Current use of any ophthalmic or systemic steroid which may interfere with this investigation. Severe, unstable or uncontrolled cardiovascular, renal, or pulmonary disease.

Ages Eligible for Study
-----------------
Minimum Age: 30 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Combigan®<br>Combigan® (fixed combination of brimonidine tartrate 0.2%/timolol maleate 0.5% ophthalmic solution). One drop of study medication taken approximately 12 hours apart, dosed 2 times a day for a total of two weeks. | Drug: fixed combination of brimonidine tartrate 0.2% timolol maleate 0.5% ophthalmic solution<br>* 1 drop of study medication taken approximately 12 hours apart, dosed 2 times a day for a total of two weeks<br>* Other names: Combigan®;|
| Active Comparator: Cosopt®<br>Cosopt® (fixed combination of dorzolamide hydrochloride - timolol maleate ophthalmic solution). One drop of study medication taken approximately 12 hours apart, dosed 2 times a day for a total of two weeks. | Drug: fixed combination of dorzolamide hydrochloride timolol maleate ophthalmic solution<br>* 1 drop of study medication taken approximately 12 hours apart, dosed 2 times a day for a total of two weeks<br>* Other names: Cosopt®;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Retrobulbar Blood Flow (Peak Systolic Velocity) as Measured by Color Doppler Imaging in the Nasal Short Posterior Ciliary Artery | Peak systolic velocity (PSV) of retrobulbar blood flow as measured by color Doppler imaging (CDI) in the nasal short posterior ciliary artery after 1 month of treatment. CDI is a high-resolution ultrasound system which provides visualization of the flow of blood through a vessel. PSV is the maximum blood flow speed within a vessel at the time of systole (maximum pressure exerted in a blood vessel). | 1 Month | 
| Retrobulbar Blood Flow (End Diastolic Velocity) as Measured by Color Doppler Imaging in the Nasal Short Posterior Ciliary Artery | End diastolic velocity (EDV) of retrobulbar blood flow as measured by color Doppler imaging (CDI) in the nasal short posterior ciliary artery after 1 month of treatment. CDI is a high-resolution ultrasound system which provides visualization of the flow of blood through a vessel. EDV is the maximum blood flow speed within a vessel at the end of diastole (minimum pressure exerted in a blood vessel in between heart beats). | 1 Month | 
| Retrobulbar Blood Flow (Peak Systolic Velocity) as Measured by Color Doppler Imaging in the Temporal Short Posterior Ciliary Artery | Peak systolic velocity (PSV) of retrobulbar blood as measured by color Doppler imaging (CDI) in the temporal short posterior ciliary artery after 1 month of treatment. CDI is a high-resolution ultrasound system which provides visualization of the flow of blood through a vessel. PSV is the maximum blood flow speed within a vessel at the time of systole (maximum pressure exerted in the blood vessel). | 1 Month | 
| Retrobulbar Blood Flow (End Diastolic Velocity) as Measured by Color Doppler Imaging in the Temporal Short Posterior Ciliary Artery | End diastolic velocity (EDV) of retrobulbar blood flow as measured by color Doppler imaging (CDI) in the temporal short posterior ciliary artery after 1 month of treatment. CDI is a high-resolution ultrasound system which provides visualization of the flow of blood through a vessel. EDV is the maximum blood flow speed within a vessel at the end of diastole (minimum pressure exerted in a blood vessel in between heart beats). | 1 Month | 
| Retrobulbar Blood Flow (Peak Systolic Velocity) as Measured by Color Doppler Imaging in the Ophthalmic Artery | Peak systolic velocity (PSV) of retrobulbar blood flow as measured by color Doppler imaging (CDI) in the ophthalmic artery after 1 month of treatment. CDI is a high-resolution ultrasound system which provides visualization of the flow of blood through a vessel. PSV is the maximum blood flow speed within a vessel at the time of systole (maximum pressure exerted in a blood vessel). | 1 Month | 
| Retrobulbar Blood Flow (End Diastolic Velocity) as Measured by Color Doppler Imaging in the Ophthalmic Artery | End diastolic velocity (EDV) of retrobulbar blood flow as measured by color Doppler imaging (CDI) in the ophthalmic artery after 1 month of treatment. CDI is a high-resolution ultrasound system which provides visualization of the flow through a vessel. EDV is the maximum blood flow speed within a vessel at the end of diastole (minimum pressure exerted in a blood vessel in between heart beats). | 1 Month | 
| Retrobulbar Blood Flow (Peak Systolic Velocity) as Measured by Color Doppler Imaging in the Central Retinal Artery | Peak systolic velocity (PSV) of retrobulbar blood flow as measured by color Doppler imaging (CDI) in the central retinal artery after 1 month of treatment. CDI is a high-resolution ultrasound system which provides visualization of the flow of blood through a vessel. PSV is the maximum blood flow speed within a vessel at the time of systole (maximum pressure exerted in a blood vessel). | 1 Month | 
| Retrobulbar Blood Flow (End Diastolic Velocity) as Measured by Color Doppler Imaging in the Central Retinal Artery | End diastolic velocity (EDV) of retrobulbar blood flow as measured by color Doppler imaging (CDI) in the central retinal artery after 1 month of treatment. CDI is a high-resolution ultrasound system which provides visualization of the flow of blood through a vessel. EDV is the maximum blood flow speed within a vessel at the end of diastole (minimum pressure exerted in a blood vessel in between heart beats). | 1 Month |