My ON started on Maui when I was unaware that I needed to stay out of the sun. I had been riding in the passenger side of the car with my arm and face in the sun. When we got to the condo I had a raging headache (almost never have them) and double vision, which lasted for eight years. Yes, sudden onset but didn't go away quickly. Went away as suddenly as it arrived. I felt a click in my eye and it was gone. I think it was all in the right eye. I often wore a patch over it to keep out the light, and could not watch TV or movies, even with the patch on.

One interesting thing about my ON or whatever it should be called was that doctors could not see it on exams, and the first one on Maui declared I did not have it. However Optic tests of nerves did show damage, and then the MRI showed sclera on the brain (not done for a year after I got the ON), about 9 or so of them, on the opposite side of the brain from the affected eye. Generally poor diagnostics until I had the nerve test and MRI.

I have not had sudden onset/departure of double vision but I have acquired some problems of old age now...getting new glasses.