It is hard to tell whether it will lead to permanent blindness or not. Optic neuritis refers to inflammation of optic nerves connecting eyes to the brain. In the first two weeks, patients with optic neuritis would have vision dimished seriously that many experienced light sensation loss. But most patients would have vision restored within 3 months. Patients also experienced pain in eyes. Optic neurities is always associated with other systemic disease, for examply hypertension and diabetes. It is better to have an examination if you are diagnosed with optic neurities. In many cases, doctors would give patients vitamin B1 and B12 intramascular injection, for vitamin B1 deficiency is the leading cause of optic neuritis. You should stay away from smoking and alcohol. Live a regular and healthy life.