A total of 44 eyes of patients with suspected glaucoma or ocular hypertension were examined both by ocular pressure tonometry (OPT) according to Ulrich and by tonography according to Leydhecker. The visual fields of these eyes were prospectively followed up for 3 years to compare the prognostic value of the two methods. In 30 of the 44 eyes a worsening visual field loss was observed, while in 14 the visual fields showed no change. Much better correlation was noted between values obtained by OPT and changes in visual field than between values obtained by tonography and visual field loss. Conventional tonography yielded 39% of false-negative values, but only 11% were recorded with OPT. Therefore, according to results of these and further investigations, OPT appears to be a more helpful and reliable method for assessment and decisions on therapy in patients with suspected glaucoma or ocular hypertension.