Serum brain-derived neurotrophic factor in glaucoma patients in Japan: An observational study.

PURPOSE: The aim of this study was to measure the serum levels of brain-derived neurotrophic factor (BDNF) in primary open angle glaucoma (POAG) and normal tension glaucoma (NTG) patients in Japan. METHODS: This was a prospective, observational study that examined serum BDNF levels in 78 patients who underwent cataract surgery or trabeculectomy (27 glaucoma patients and 51 non-glaucoma cataract patients as controls). The patients' age was 68.8 +/- 11.1 years (mean +/- standard deviation; range 35-86 years). The number of patients with POAG and NTG was 16 and 11, respectively. The diagnosis of POAG was done by intraocular pressure measurement, gonioscopy, optic nerve head change, and the presence of a visual field defect. RESULTS: The serum BDNF concentration was significantly lower in the glaucoma group, including both POAG and NTG, than in the control group (7.2 +/- 3.6 ng/mL vs. 12.2 +/- 9.3 ng/mL, p=0.004). The serum BDNF concentration was lower in the early phase than in the moderate phases of glaucoma. There was no correlation between the serum BDNF concentration and age. When the NTG and POAG patient groups were compared, the serum BDNF concentration was lower in NTG patients than in POAG patients. No significant correlations were found between glaucoma parameters, including optical coherence tomography and visual field defects, and the serum BDNF concentration. CONCLUSION: This is the first study to have investigated serum BDNF concentrations in glaucoma patients in Japan. Further investigations are needed to evaluate the role of BDNF as a potential biomarker of glaucoma.