The purpose of this study is to evaluate the additive intraocular pressure (IOP) lowering effect of Brinzolamide 1%/Brimonidine 0.2% (SIMBRINZA®) dosed twice daily (BID) when added to Travoprost 0.004%/Timolol 0.5% (DUOTRAV®) in subjects with open-angle glaucoma or ocular hypertension.