Comparative Study of Dorzotimol Eye Drops, 20 mg/mL + 5 mg/mL Versus Cosopt® Eye Drops, 20 mg/mL + 5 mg/mL

Inclusion Criteria: * Females or males in the age bracket of 18 to 75 years. * Established stage I and II primary open-angle glaucoma in one or both eyes. * Intraocular pressure (IOP) level: 22-36 mm Hg (by Goldmann applanation tonometry). * Visual acuity 0.3 or better on the tested eye. * Taking topical prostaglandin analogs as monotherapy at least 3 months prior to the enrollment into the study and poor IOP control (\> 21 mm Hg) or failure to achieve the target IOP, as estimated by the physician. * Patients who have signed an informed consent to participate in the study. * For females of child-bearing potential - a negative pregnancy test and consent to use reliable contraception methods throughout the study Exclusion Criteria:• Contraindications or hypersensitivity to the active ingredients (dorzolamide and/or timolol) or excipients. * The only eye. * Visual acuity ˂ 0.3 after correction. * An active infectious inflammatory process on the tested eye within 3 months prior to pre-study medical examination. * Pronounced visual field defects (III and IV stage open-angle glaucoma). * IOP \> 36 mm Hg or \< 22 mm Hg as at the IOP measuring at 11:00 a.m. (±1 h) in any of the eyes on the screening visit day. * Closed or nearly closed anterior chamber angle (ACA) or history of acute angle close. * Surgical and laser eye interventions over the last 3 months. * Manifest ocular media opacification hindering the treatment efficacy evaluation. * Other eye diseases that may affect dyna…