[Psycho]

All MR checks in the game are against base value of 12, for all items and spells. Sure you can blind a MR 32 creature, but that requires a great deal of luck. Lama, I guess you just had luck with the eye shield or maybe your opponents didn't bring enough MR to the table. But it's not something you can rely on and if the eyeloss effect doesn't work, then you brought along a near-worthless parry 5 shield. It's easy to blind a bunch of knights or jags if they can't kill you fast enough. But then it means that they probably wouldn't be able to kill you anyway.