This sense of isolation helps to demonstrate his obstinate close-mindedness, most apparent in his feelings and pre-conceived notions of blindness.
As he admits, his idea of blindness comes from the movies. It very much gives reassures that personal understanding of the truth, understanding of the things beyond your physical sight are far more important that the physical.
The fake-out prayer that the narrator uses is a bit befuddling in terms of story, unless you think of it as a set-up for the later conversation.
The characterization does a lot to disguise the narrator's primary problem: he is detached from his life.
Drug and alcohol usage throughout the entire story significantly adds to another blindness of which the subject is oblivious. Although the ending is in one way or another predictable, it, nonetheless, gives the reader something to meditate upon long after finishing the story.
This brief experience will have a life long effect on him.
The story climaxes after the wife falls asleep and the two men are finally allowed to converse with each other. But it was empty.