Inclusion Criteria:

• Adult patient with newly diagnosed and untreated for open-angle glaucoma or ocular hypertension with an IOP of > 27 mmHg (in at least one eye) and a baseline GSS SYMP-6 total score of 75 or less
• Patient is male or a female who is highly unlikely to conceive
• Patient has been recently diagnosed and is presently untreated for open-angle glaucoma or ocular hypertension with an IOP of at least 27 mmHg in at least one eye (patient's worse eye)
• Patient already diagnosed with open-angle glaucoma or ocular hypertension and untreated for at least 30 days are eligible for the study if they have an IOP of 27 mmHg or more in at least one eye

Exclusion Criteria:

• A history of any illness that, in the opinion of the investigator, might confound the results of the study or pose additional risk by administering preservative free dorzolamide-timolol (preservative-free Cosopt®)
• The presence of any fundus pathology likely to change during the study or to influence IOP (background of diabetic retinopathy is permitted)
• Any contraindication to the use of preservative-free Cosopt® including:
• bronchospasm, including bronchial asthma or a history of bronchial asthma or chronic obstructive pulmonary disease, sinus bradycardia, second or third degree AV block, cardiac failure (grade III and IV), cardiogenic shock, severe renal impairment (serum creatinine > 150 umol/L or creatinine clearance < 30 ml/min)
• Patient on:
• carbonic anhydrase inhibitor, concomitant systemic or dermatological medication known to affect the IOP, e.g. clonidine, corticosteroids, oral beta-blocking agents. patient on a non-glaucoma medication that contains a preservative agent, i.e. benzalkonium chloride, benzododecinium bromide or stabilized oxychloro complex
• Patient with hypersensitivity to any component of preservative free dorzolamide-timolol (preservative-free Cosopt®)