RESUMO
PURPOSE: This study was designed to compare the levels of brain-derived neurotrophic factor (BDNF) in the serum and aqueous humor (AH) of patients with primary open-angle glaucoma (POAG) and normal-tension glaucoma (NTG). METHODS: This prospective, observational study consists of 30 patients with POAG, 30 patients with NTG, and 30 healthy controls. The serum and AH BDNF levels were assessed using an enzyme-linked immunosorbent assay. RESULTS: BDNF levels in serum and AH were markedly lower in the glaucoma groups (POAG and NTG) than in the control group (p < 0.05). When comparing the NTG and POAG groups, the average serum BDNF level was significantly lower in the NTG group than in the POAG group (p < 0.05). The difference in the mean BDNF levels in AH between the POAG and NTG groups was not statistically significant. (p = 0.538). CONCLUSION: We confirmed that serum BDNF levels were lower in patients with NTG than in those with POAG. BDNF could be a causative systemic biomarker in NTG.