Sorry to resurrect such an old thread but the permanent blindness bug with Valen still exists and its a pain in the butt to solve! Valen was permanently blinded after fighting the Eclipse party, I don't know if it was because they beat her to a pulp with their blinding weapons or the infamous Nature's Beauty spell. I'm not convinced it's a problem with Nature's Beauty that causes the issue and I'll explain why abit later.
I'm using v43 of Valen and the only spells I've found that rid of the blindness are Cure Disease and Neutralize Poison (Malla's Soul Stone is handy for this).
Dispel magic only removes the display icon but not the blindness effect (THAC0 and sight radius).
Heal, Slow Poison, Elixirs of Health, or a Rod of Resurrection don't work, presumably because Valen is 'immune' to healing magic? This includes using Heal at a temple or with items etc.
The reason I think this may be a Valen bug and not just Nature's Beauty misbehaving is that the first way I fixed it before thinking to try Cure Disease was using Shadowkeeper to change Valen's Sun variable back to what it was before the Eclipse fight (By copying, removing and pasting the variable). This seemed to fix it although if the Sun variable keeps on changing naturally perhaps Valen would have become incorrectly blinded again once it got to a certain value?
I'm just looking for clarification really, is this a Valen only bug or is it a known problem with Nature's Beauty that sometimes Dispel Magic doesn't work properly? Regardless maybe a note should be added to the readme since Valen can't be cured by Dispel or Heal etc, someone might not necessarily think to try lower level spells if Heal didn't work!
Sorry if this is all abit presumptious and its just a problem with my much modded install, but I thought I should bring it to your attention!