PARP1 and open-angle glaucoma: In an effort to combat oxidative stress, SOD and GPx activity have been shown to be increased in aqueous samples of POAG patients [98,111,112]; however, their protective capacity can be overwhelmed and we see a cumulative rise in ROS as indicated by raised aqueous levels of 8-OHdG and a reduced expression of base excision repair (BER) markers, poly (ADP-ribose) polymerase 1 (PARP1) and oxoguanine DNA glycosylase 1 (OGG1) [113].