Inclusion Criteria: Patients fulfilling two out of three of the following criteria in one or both eyes: a) typical glaucomatous disc, b) visual field damage (a cluster of three points (except rim points) in at least one hemifield reduced by 5 dB or greater and including at least one point reduced by 10 dB or greater; a cluster of two points reduced by 10 dB or greater; or three adjacent points on the nasal horizontal meridian that differed by 5 dB or greater from their mirror points on the opposite side of the meridian), c) intraocular pressure above 21 mm Hg at least at one occasion. Furthermore, patients need to have a series of at least 5 visual field examinations, after exclusion of the first test, for assessment of progression.