It has long been rumored that a final scene, in which Dr. Xavier screams "I can still see!" was cut by censors. No footage of this is known. However, the movie does end rather abruptly just as Dr. Xavier seems about to say something, and those words would provide a chilling climax to the story. This rumor is false according to Corman - In a Q&A with Corman he said this idea was discussed but never filmed.
This film originally had a five minute prologue about the human senses. This prologue was removed from all post-theatrical prints of the film, and may have been removed from some of the theatrical release prints. This reduced the running time to 79 minutes. The footage still exists.
To create the effect of being able to see through a building, the director filmed the construction of the building in time lapse, then ran the film backward.