MOG and optic nerve disorder: VEP recording has been used to estimate loss of RGCs and axons in several optic neuropathy models.33, 34, 35 Notably, delayed VEP latencies correlate with ON demyelination and axon loss in MS patients.36, 37 We recorded the VEP from mice 1 week before MOG immunization (baseline) and at 5 WPI (end point).