I have had a rather hard thing to explain for more than 6 years now so I'll try to explain.
My vision will double a ghostly vision only upwards and generally only half way not fully. I've had 2 mri's many eye appointments and they still found nothing. I was thinking it's more Neurological since it affects both eyes the same way. It only happens to brighter objects and gets worse at night.
I also noticed an odd thing that my left pupil is sometimes bigger than my right, and seems like my left eye is becoming a bit lazy...
I have prescription for my eyes but it does not help the doubling of things that happens to me.