AQP4 and neuromyelitis optica: The current research results show that the effect of NMOSD on the retina is mainly caused by the combination of NMO-BIG and AQP4 in astrocytes of the retinal nerve fiber layer (Brosnan and Raine, 2013; Vaknin-Dembinsky et al., 2014; Sofroniew, 2015; Chen et al., 2020).