[Normal pressure glaucoma: a diagnostic challenge].
PURPOSE: Normal-tension glaucoma (NTG) is a frequently discussed optic neuropathy. The purpose of this retrospective study was to evaluate the final diagnosis of patients with presumed NTG and to select the best distinguishing examination methods. PATIENTS: All patients with presumed NTG hospitalized for diurnal IOP curves from 1987-1992 were studied. We evaluated retrospectively which diagnostic tests contributed most to the final diagnosis. RESULTS: In 26 out of 50 patients with presumed NTG the final diagnosis had to be changed, mainly because the diurnal IOP curve showed a dysregulation; often only the early-morning IOP in supine position was elevated. CONCLUSIONS: We suggest that early-morning IOP spikes are one of the important pathogenetic factors in patients with glaucomatous changes without other pathology. Early morning IOP measurement in supine position before rising should therefore be a mandatory part of diurnal IOP curves in patients with presumed NTG.