We evaluated the association between hair lead concentrations and primary open-angle glaucoma. Ninety-eight Japanese patients (40 males, 58 females; average age 57.6 ± 10.8 years) with primary open-angle glaucoma and control subjects (131 males, 114 females; average age 56.0 ± 12.8 years) were recruited in this study. Hair lead levels were measured by inductively coupled plasma mass spectrometry. Hair lead concentrations between primary open-angle glaucoma and control groups were compared using Mann-Whitney U test. As a subgroup analysis, we compared hair lead concentrations between low-tension glaucoma, high-tension glaucoma, and control groups using one-factor analysis of variance. Lead accumulation levels were significantly higher in the female subjects with primary open-angle glaucoma compared to the control group (P=0.03). Lead accumulation levels were significantly higher in female patients with low intraocular pressure compared to control group 2 (P=0.02). A higher hair lead level, which reflects the total body burden of lead, was observed to be associated with primary open-angle glaucoma in females especially with low-tension glaucoma. Accumulation of lead may be an unrecognized risk factor of non-pressure-dependent glaucomatous optic neuropathy.