In Anaïs Nin's "House of Incest," the author conveys a deep sense of inner turmoil through the imagery of a "crack in my vision." This metaphor reflects a fractured perception of reality, indicating that the narrator's view of the world is impacted by personal chaos or emotional distress. The notion of madness seeping through this crack suggests a struggle with mental instability, highlighting the fragility of the mind when faced with overwhelming experiences.

The statement implies that the disturbances in the narrator’s psyche are ever-present, reinforcing the idea that madness is an ongoing challenge rather than a temporary state. This exploration of the mind's fragility is central to Nin's work, as she delves into themes of desire, identity, and the complexities of human experience. The raw vulnerability expressed in this quote invites readers to reflect on their own perceptions and the influence of inner demons on one's understanding of reality.