 The investigators will investigate the OA blood flow, intraocular pressure IOP and structural properties of the optic nerve. The investigators will include glaucoma patients as they believe that glaucoma may be caused by or influenced by OA blood flow. The investigators will include also patients with intraocular hypertension with and without pseudoexfoliation in order to study how changes in IOP interact with OA blood flow and the structural properties of the optic nerve in a group that does not develop glaucoma. In addition, the investigators will investigate patients that develop glaucoma in spite of a normal IOP. Therefore, the investigators will study three fundamentally different groups G1, G2 and G3 of patients as well as a control group of healthy subjects G4: 