Will optic neuritis kill me or make me blind?

Not lethal: Optic neuritis will not cause mortality. However, unless it spontaneously improves or if treatment given is effective, it might progress to visual deficit that can be severe and rarely blindness.

Depends: Optic neuritis can be a sign of multiple sclerosis or ms. Ms can cause many physical changes that can be mild to severe it can also cause death. Thus an eye exam is really recommended.