Subjects and Methods The present protocol intends to explore the response of a major temporal superior and inferior retinal artery and vein to a 60 seconds 12.5 Hz flicker light stimulation in 50 glaucoma patients, 50 ocular hypertensives and 50 controls (using the Retinal Vessel Analyzer) and to investigate how intraocular pressure relates to neurovascular coupling. In addition, 50 glaucoma patients and 50 ocular hypertension patients will be followed for 3 years for functional (visual field, automated perimetry with Octopus device) and morphological (retinal nerve fiber layer thickness, Optical Coherence Tomography Stratus OCT device) glaucomatous damage progression, in order to test the predictive power of the retinal vascular flicker response for glaucoma progression. Patients will be recruited in the University Eye Clinic Basel, a notification in the University Hospital of Basel and/or advertisement in a newspaper will inform potential healthy volunteers of the opportunity to participate in a scientific research project.