How long does the blurred vision last for multiple sclerosis?

Depends on duration.: If you have an acute attack of optic neuritis and blurred bison it may subside by treatment. However if your blurred vision is older than a few months and there is no activity on oct and MRI then it may last the way it is.

Variable: Blurred vision for multiple sclerosis is due to optic neuritis. This is due to inflammation in the nerve connecting the retina to the brain. Most vision recovers after 12 months. Sometimes patients are left with permanent diminished vision.

If optic neuritis: I presume you refer to optic neuritis, which if appropriately treated should resolve over 6-8 weeks at most usually.