The aim of this dose-finding clinical trial is to evaluate the systemic tolerability, local tolerability and intraocular pressure lowering effect of three different doses of SYL040012 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