The objective of this research study is to compare the tolerability and effectiveness of Combigan(brimonidine tartrate/timolol maleate) and Cosopt (dorzolamide hydrochloride)in the treatment of open angle glaucoma or ocular hypertension.

Patients between the ages of 40 to 90 years of age, that have been diagnosed with open angle glaucoma or ocular hypertension,including pseudo-exfoliation and pigmentary glaucoma with definitive glaucomatous optic disk cupping and/or glaucomatous visual field loss, who have been recieving a stable treatment regime for at least 4 weeks prior to the study initiation, with a Cosopt mono or a Prostaglandin + Cosopt combination are to be included in the study.Patients must have an IOP between 16 and 32 mmHg, with no readings above 35 mmHg at baseline.

Patients with any other form of glaucoma other than primary open angle glaucoma, with a gonioscopy measured angle grade of less than 2, with a visual field defect not of glaucomatous origen and previous cyclodestructive procedures will be excluded.The use of ocular non steroidal and anti-inflammatory topical agents which inhibit cyclooxygenase and prostaglandin analog synthesis,the use of glucocorticoid therapy, and hypersensitivity to any of the study components also precludes involvement in the study. Any ocular laser therapy within the past three months, ocular inflammation or infection in the past three months or any history of trauma in the last six months will also exclude enrollment in the study.

• Open Angle Glaucoma
• Ocular Hypertension

Inclusion Criteria:

• open angle glaucoma or ocular hypertension including pseudo-exfoliation and pigmentary glaucoma
• definitive glaucomatous optic disk cupping and/or glaucomatous visual field loss
• a stable treatment regime for at least 4 weeks prior to the study initiation, with a Cosopt mono or a Prostaglandin + Cosopt combination
• an IOP between 16 and 32 mmHg, with no readings above 35 mmHg at baseline

Exclusion Criteria:

• any other form of glaucoma other than primary open angle glaucoma
• a gonioscopy measured angle grade of less than 2
• a visual field defect not of glaucomatous origen
• previous history of cyclodestructive procedures
• the use of ocular non steroidal and anti-inflammatory topical agent that inhibit cyclooxygenase and prostaglandin analog synthesis
• the use of glucocorticoid therapy
• hypersensitivity to any of the study components
• any ocular laser therapy within the past three months
• ocular inflammation or infection in the past three months
• any history of trauma in the last six months