After reading a Black Book and returning to Solstheim, there is (still) a very headache-inducing blur effect. Nothing seems to remove this. Is this removable (via console or mod or), or do I have to revert to a prior save?

Radeon 6670 (2GB RAM), latest Catylyst drivers, XP SP3.

If that's a bug, probably you should load a previous save. !!!!

I have read about that tunneling blur effect over the net, and it seems that's a game glitch actually.

Have you installed the unofficial skyrim and DLC patches ???

Yup. Never play without them. But there isn't that much they can do about engine glitches, unfortunately.

unfortunately., you have right....