As a reader, our sympathies for Robert are stimulated when we first learn that he is blind; however, the compassion is fully realized when we read of Robert attempting to navigate the front walk and enter the narrator's home. For the narrator, however, his compassion is much more hesitant and reserved. It isn't until he learns and thinks about Robert's wife knowing Robert could never see her that he first begins to feel compassionate toward the man.
In all ways, the narrator of "Cathedral" is insensitive and fairly obtsue about others and their emotions. However, it is this resistance that drives the story and allows it provide the emotional impact that it does for the reader.