To compare the visual field defects in the late stage of disease between normal-tension glaucoma (NTG) and primary open angle glaucoma (POAG), measurements taken with the 30-2 and 10-2 threshold program of the Humphrey Visual Field Analyzer were analysed by statistical methods including logistic discriminant analysis. Thirty-four eyes of 34 NTG cases and 63 eyes of 63 POAG cases whose mean deviation (MD) given by STATPAC was equal to or less than -15 dB were included and there was no significant difference in MD, refraction, or age between the two groups. The analyses demonstrated that the upper arcuate area was significantly more depressed in POAG and the inferior Bjerrum area was significantly more depressed in NTG eyes. It was also shown that the lower papillo-macular area was less affected in NTG than in POAG eyes.