Computerized disc analysis was used for the longitudinal monitoring of patients with moderate intraocular pressure elevation. 44 patients (80 eyes) were monitored for at least 18 months; 25 patients (47 eyes) were monitored for at least 12 months; 15 patients (25 eyes) were monitored for at least 18 months. On average, one computerized disc analysis was performed every 4 months. Eight eyes showed a progressive decrease in their neuroretinal rim area. Seven of them were monitored for more than 18 months, one was monitored for 15 months. In all cases, the progressive decrease in neuroretinal rim area was significant, p less than or equal to .1. It is non-physiological and has to be interpreted as a serious sign of ongoing glaucoma damage. In addition, it obviously precedes the onset of visual field defects. Seven out of 8 eyes with progressive decrease in their neuroretinal rim area have normal visual fields up to now. In one case a progressive decrease in neuroretinal rim area was found at first and small visual field defects developed subsequently.