The only actual event that occurs in the prologue is the narrator's conflict with the blonde man in the middle of the night. The narrator beats the man to near his death before he realizes that the man is blind. Like the invisibility mentioned at the start of the prologue, this blindness is also not physical, but rather metaphorical. The blonde man, like all of society, is "blind" in the sense that they are unable to see the narrator or any other blacks for anything besides their skin color. This blindness is then not a physical disability, but a social predisposition that causes the isolation the narrator feels with the rest of society.
To the narrator, his invisibility and the blindness of others can be seen as almost an advantage. He is able to do things and avoid repercussions as he is often overlooked. He thinks it is his invisiblity that allowed him to avoid being punished for his assault of the blonde man or for stealing electricity. It is almost as if his invisibility and society's blindness removes him from society and puts him on another level of existence, whether that level is above or below the rest of the world remains unknown. Nevertheless, his isolation from society is clearly represented in the prologue as he introduces his living quarters. He lives physically isolated and below a building full of whites. In a physical sense, he is below society; however, his lack of blindness and ability to see the true reality of the world puts him above society in the plane of knowledge.
The basement that the narrator lives in may be the most important part of the prologue. The idea of an abandoned basement resembles an isolated and antiquated world, forgotten in time. When he is in his basement, he is separate from the rest of the world. His obsession with light is incredibly revealing of how the narrator views himself. Light connotes vision, knowledge. The huge number of lights in his basement represents his propensity for knowledge as he is on a higher plane of reality. However, it could also represent his struggle to define himself in a world that is unable to see him. In this sense, his invisibility is actually a restraint that prevents the narrator from existing in the real world. He is invisible, in that case, not only to society, but also to himself.