The results were consistent with the findings of previous studies showing that pRNFL thickness loss was mainly involved in superior, inferior and N quadrants in NMO-ON eyes when controlling for contrast sensitivity[17, 20, 30].However, most studies demonstrated that NMO-ON preferentially damaged superior and inferior quadrants of pRNFL[16, 31].These differences may be associated with the enrolled NMOSD-ON patients, such that only ON patients with AQP4-Ab seropositivity were included in the present study. Here, AQP4 is linked to neuromyelitis optica.