Dose Finding Clinical Trial With SYL040012 to Evaluate the Tolerability and Effect on Intraocular Pressure in Subjects With Ocular Hypertension or Open Angle Glaucoma

Inclusion Criteria: * Subjects must provide signed informed consent prior to participation in any study-related procedures. * Male and female subjects in good or fair general health as assessed by the investigator. * ≥18 years of age. * Previous history or newly diagnosed elevated IOP (≥21 mmHg) with or without open-angle glaucoma in both eyes. * Normal result, or result typical for open-angle glaucoma of the following assessments in both eyes or available results in writing within the last 3 months prior to baseline period i.e. up to 4 months before Day 1, on condition that no new ocular signs or symptoms (e.g. marked deterioration of vision, eye pain) has occurred since then which would justify a repeat examination: * Visual field 24-2 or equivalent * Optical coherence tomography (OCT) * Best corrected visual acuity ≥0.5 (20/40) on the Snellen chart, or ≤ 0.3 logMAR * Schirmer test (lacrimation) * Funduscopy Exclusion Criteria: * Pregnant or breastfeeding females or those with a positive pregnancy test. Females of childbearing potential who will not use a medically acceptable contraceptive method from selection and during the hole study. * Females of childbearing potential not willing to use a medically acceptable contraceptive method from enrolment until after the follow-up visit. * Any current disease or condition that might compromise the respiratory, cardiovascular, endocrine, neurological, haematological, renal, or gastrointestinal function. * Previous chronic processes or with rebound characteristics that could interfere with the study according to the investigator's judgment. * Body temperature. * Intolerability of any components of SYL040012 or placebo. * Unable to comply with the clinical trial requirements as judged by the investigator. * Beta blockers or corticosteroids use (other than cutaneous or intra-articular) for the treatment of concurrent diseases, even if sporadically, or any ocular or nasal vasoconstrictor treatment in the last 15 days prior to the first investigational product administration * Previous refractive surgery; cataract extraction in the last 6 months * Previous surgery for glaucoma. * Participation in a clinical trial within 2 months before the enrolment visit * Use of any other investigational product within 60 days before the enrolment visit. * Other drugs for the treatment of concurrent diseases are allowed. However, their dosages should be kept constant throughout the study. * Use of contact lenses in the last 7 days prior to the first investigational product administration and wearing contact lenses throughout the trial * History of ocular infection or inflammation within the last 3 months before the enrolment visit * Angle-closure or pigmentary glaucoma. * Chronic or current acute eye diseases such as scleritis, uveitis, blepharitis, conjunctivitis, or ocular Herpes simplex virus infection