BDNF and open-angle glaucoma: A statistically significant increase in the frequency of the C/T BDNF genotype (OR 1.72; 95% CI, 1.23–2.39; P < 0.001) and T/T BDNF genotype (OR 2.06; 95% CI, 1.36–3.12; P < 0.001) as well as T BDNF allele (OR 1.45; 95% CI, 1.19–1.78; P < 0.001) in patients with POAG in comparison with control group.