Cosopt (Timolol/Dorzolamide) This product contains two drugs used to treat high pressure inside the eye due to glaucoma (open angle-type) or other eye diseases (e.g., ocular hypertension). Lowering high pressure inside the eye helps to prevent blindness. This medication works by decreasing the amount of fluid within the eye. Timolol belongs to a class of drugs known as beta-blockers, and dorzolamide belongs to a class of drugs known as carbonic anhydrase inhibitors.