Like Hazel says, cataracts are more an age related thing, than an MS thing.
I was told by an optometrist I really trusted that I had an incipient cataract in my left eye( this was about 10 years back).
This was confirmed by an opthalmologist about 4 years later.
An eye-test last month said incipient cataract in right eye and nothing in left.
Now the optometrist (way back) said that they could develop quite quickly, or very slowly, and could come or go in the earlier stages.
One problem with blurred vision can be that the secretion that keeps the eyeball clean when you blink can get a bit thick for some reason, and smears rather than cleans - in this case, a lot of frantic blinking can clear it. I do not know why this happens.
The only thing I know for sure is that HBOT can trigger an incipient cataract into development. This is the only reason why I have not gone for HBOT myself.
On the positive side, when you have the cataracts done, you can end up with excellent vision without glasses (and can go and buy a really cool pair of shades for when the sun shines.