The proposed crossover study will compare for the first time the quality of 24-hour intraocular pressure control with the combination of travoprost and brinzolamide/timolol compared with travoprost and brimonidine/timolol in glaucoma patients insufficiently controlled with travoprost. This comparison may determine the real efficacy of the two fixed combinations when added to the prostaglandin. The design of the proposed study should facilitate a better understanding of the role of these medications in glaucoma management.

Inclusion Criteria:

• Patient has open-angle glaucoma and is older than 29 years
• Patients should exhibit typical disc, or field changes and an untreated morning IOP greater than 25 mm Hg
• Patients are treated for at least 3 months with travoprost and should have demonstrated at least a 20% morning IOP reduction
• Patient deemed by PI to require adjunctive therapy to obtain desired target IOP
• Patient should exhibit IOP greater than 18 mm Hg on travoprost monotherapy (2 separate IOP readings at 10:00)
• Patient has mild to moderate glaucoma (field loss more than 16 dB; cupping 0.8 or less)
• Distance best corrected Snellen visual acuity at least 0.1
• No contraindications to travoprost, brimonidine, brinzolamide and β-blockers
• No history of lack of response (<10% morning IOP reduction) to any medication
• Patient can understand the instructions and adhere to medications

Exclusion Criteria:

• Female patient of childbearing potential or lactating mother
• History of trauma, inflammation, surgery
• History of past use of steroids (within 2 months), severe dry eyes and use of contact lenses
• Signs of ocular infection, except blepharitis
• Evidence of corneal abnormality that may affect IOP measurements etc
• Closed angle
• History of non-compliance