Primary open angle glaucoma may be a severe ocular disease and may lead to blindness if not diagnosed and/or treated in time. The pathogenic mechanism is a progressive loss of ganglion cells leading to cupping of the optic nerve head. The main risk factor is an elevated intraocular pressure, but optic nerve vascular deficiency, neuronal degeneration or genetic factors have to be considered as other potential risk factors. The actual diagnostic tools and the latest technologies for the medical, laser and surgical treatment are described in this paper.