Optic nerve. Nerve cells cannot regenerate (repair themselves). This means that any damage you have to one of your nerves is permanent (most likely). However, research is targeting nerve injury and regeneration at the current time.
Optic nerve. There is no surgery to repair a damaged optic nerve. However there is a lot of research investigating ways to do this in animal models which someday may become possible in humans. We now have fda approval of a retinal prosthesis for people with vision loss due to retinal disease. Something similar for optic nerve disease may be possible in the future with much more research.