I had the exact samething happen when I entered a cave and then exited the cave at the other end. I didnt notice it at first cause it was night time. So, the way I fixed it was to go back to the cave entrance and enter, then turn around and exit. This fixed the blurr/fuzzy problem. The cave where it happened to me at is the NCR outpost called Camp Guardian, east of Valut 34, east of Bitter Springs Recreation Area. Also, one thing to note, at least on my PC anyway, is that as soon as I enter the cave it is pitch black. If I take a few steps forward into the cave it lights up again. I think this is the issue/bug because if you travel all the way through the cave and exit at the other end, you will have the blurr/fuzzyness with the screen.
I think I can actually help on that. I think the bug is actually location-specific.
It didn't start happening to me until I left the REPCONN facility headquarters. I might check that out and see if it fixes it, as well as trying the mentats solution posted above.
Also, a note for anyone who has this bug. The biggest give-away is lingering black smoke indoors in perfectly illuminated light (not entirely sure, though, would like someone to confirm on this).