Optic neuropathy as a presenting feature of vitamin B-12 deficiency: A systematic review of literature and a case report.

Introduction: Vitamin B12 (VitB12) deficiency rarely manifests with visual symptoms. Optic nerve damage in VitB12 deficiency is thought to be via degeneration. However, optic neuritis, though infrequent, has been reported secondary to VitB12 deficiency.