I have never heard that either.
IF Vader is blind then HOW can he 'look' on Luke "With my own eyes"!?!
He would still be using the force IF he was blind. So I guess your saying that the force 'see's' things differently through a piece of armor? That is rediculous!
Vader had sight, Ani had sight. Period.
Are you next going to say that All the stormtroopers were blind because they had the same type eyepeaces? Or what about Boba Fett? Blind too?
I think most of us can see who the blind one is on this one. 😉
First, it's pretty obvious that the powers of the force increase with proximity. The closer, the better. And I'm pretty sure nobody can choke ppl across the galaxy. Or use any other kind of force tricks at such interstellar distances. However, I seem to recall having read something about the emperor's mind controll actually extending all over his empire. He guided all the lesser minds under his rule, and when he died, they were all suddenly released. I don't know how much this can be trusted though. I think maybe I read it in Timothy Zahn's Heir to the Empire trilogy.
Second, it has never occured to me that Vader cannot see with his mask on. If you can tell that the mask actually is opaque, just by looking at it, then I guess poor David Prowse must have had a really hard job, staggering blindly about the set. Those lightsaber battles can't have been easy. Logically, I guess it is *possible* that Vader couldn't see through the mask, but I don't see any reason for it. If he didn't want to trust his eyes, surely, he could just stop using them. He'd have enough self control for that, without having to resort to physically blocking his eyes. But to have the *possibility* to see, in case it becomes neccesary for some reason, can't be bad. Another thing is that he didn't neccesarily have to see through the visor directly, but maybe via a set of imbedded cameras.