['To determine levels of Peptidyl arginine deiminase 2 (PAD2) and its product protein-bound citrulline in cadaver eyes that suffered from normal tension glaucoma (NTG) compared to primary open angle glaucoma (POAG), and controls.', 'Western analysis, ELISA, and immunohistochemical analysis were performed with human tissues.', 'We report over expression of PAD2 and higher levels of its product protein-bound citrulline in the optic nerve of normal tension glaucoma patients (NTG).'] Is peptidylarginine deiminase type 2 over expressed in the glaucomatous optic nerve?