This clinical trial is a prospective, controlled, study and will be performed at one clinical investigative site in Tucson Arizona1. The purpose of this study is to determine if the device, CATS tonometer prism, measures intraocular pressure significantly differently than the current standard of care tonometer prism (Goldmann) before and after institution of topical prostaglandin analogs (PGA) for glaucoma treatment. Fifty percent of patients will be randomly placed on topical beta blockers as a control. The difference PGAs and beta blockers would be a measurement of the amount of corneal biomechanical changes made due to the PGA controlled for the effect of IOP lowering by the beta -blocker group.
