Optic nerve caused blindness how to fix it?

Probably not possibl: See your neuro-ophthalmologist for a discussion of this problem. Optic nerves that are seriously damaged cannot usually be treated. There is some relationship to cause here - for instance there are a number of cases of visual loss from thyroid disease which can recover quite a bit.

Cautious use: The optic nerve is extremely complex. It contains millions of fibers and travels the entire length of the brain. Damage to this nerve may cause complete blindness that then recovers over time. The degree of recovery is almost impossible to predict or improve. Try to use the eye gently but consistently and pray for recovery over time.