The purpose of this study is to determine the intraocular Pressure (IOP) lowering response and evaluate the safety of brimonidine tartrate 0.025% ophthalmic solution in adult subjects with open angle glaucoma or ocular hypertension.

Inclusion Criteria:

• Be at least 18 years of age at Visit 1 (Screening), of either sex and any race
• Be willing and able to provide written informed consent prior to any study procedures being performed.
• Be willing and able to follow all instructions and attend all study visits.
• Be willing to discontinue use of disallowed medication
• Have a documented diagnosis of ocular hypertension, open angle glaucoma or chronic angle closure glaucoma with a patent iridotomy.

Exclusion Criteria:

• Have known sensitivity or poor tolerance to brimonidine or any other component of the study medications.
• Have any form of glaucoma other than open-angle glaucoma, ocular hypertension or chronic angle closure glaucoma with patent iridotomy.