Six months after her previous presentation of transverse myelitis, from which she completely recovered, Mandy Wallsmith returns with complaints of bilateral visual loss (worse on the right). The problem started two days ago with pain in and behind her right eye, worse when she would look to the left or right. Yesterday, she began to notice that she wasn't seeing well out of her right eye. Today her vision seems worse, although the pain is a little better. On examination, her visual acuity is found to be 20/80 in the left eye (OS) and 20/400 in the right eye (OD). Visual field appears to be normal in the left eye, but she can only detect hand motion (not finger counting) in all quadrants with the right eye. She finds that colours look less vivid with her right eye - especially red, which looks "kind of gray".