How does the long-term outcome of people with severe optic neuritis due to MS compare between people who received steroid treatment during the attack and people who were not treated?

I have seen studies that establish that steroid treatment does not affect the final visual recovery of people with optic neuritis, but I would like to see a bigger study that focuses on severe optic neuritis. How many people who are permanently blind/mostly blind in the affected eye were untreated vs treated?