What illness besides MS has optic neritious as a symptom?

Optic neuritis. Optic neuritis can be an isolated condition with no apparent cause. Long term follow up work has shown many cases of optic neuritis are not related to any condition. Optic neuropathy can also be caused by vascular disorders and neuromyelitis optica, which are both rare.
Optic neuritis. The differential diagnosis for optic neuritis is extensive and includes numerous neurologic, inflammatory, medication related, neoplastic and other causes. See an eye doctor.