To answer the question based on my own personal experience.

Yep! It can cause diplopia.

I developed optic neuritis in my left eye in August of 2006. It obscured about 2/3rds of my vision. The giant blind spots had backed off within about 3 months. But my vision was extremely dim for over a year.

I got diagnosed with MS in January of 2007. I didnt think my eye would ever improve. In June of 2007 I had a second opinion done at the local MS Clinic.

It was during that exam that I noticed that I had double vision in my right eye when I look to the right while keeping my head facing straight forward.

The diplopia is finally starting to improve a little bit. Where I'd get two distinct images while looking to the right, now I get two images that are not exactly doubled all the time.

It hasnt exactly bothered me much. Since I only see it if I look to the right. I think my body adapted to the double vision by turning my head a little bit more when looking to the right, rather than just moving my eyes.

I'm hoping it continues to improve. I think it will. My left eye is almost back to what it was before things went all wonky on me. It's been just in the last few weeks that I've noticed that when I look thru my left eye by itself, that I feel like I'm seeing almost everything and am not "missing" information coming thru the eye into my brain.

I've had at least three or four separate incidents of optic neuritis since 2006. One, might have been actually a pseudo-exacerbation when I had the flu last fall, but my eye doctor has told me that he thinks that I've had ON at least two or three times in my right eye...which, strangely enough didnt develop dyschromatopsia (loss of color vision) like my left eye did.

My left eye had the worst case of ON. It was my worst and pretty much my first big exacerbation to date too. (I had some dysthesia in my right thigh and leg for about 4 or 5 months before the ON hit...but had been told that was a pinched nerve)