There was a weak negative correlation between oxytocin concentration and MD slope (β=-0.334, p=0.084) and a weak negative correlation with central TD slope (β=-0.405, p=0.039), adjusted for age, sex, and history of additional eye drops.<h4>Conclusion</h4>Oxytocin concentrations in glaucoma patients were significantly lower than in normal subjects and associated with the severity and progression of visual field defects. This evidence concerns the gene OXT and glaucoma.