The two main symbols in the story are the old man’s eye and the narrator’s own heart. The narrator describes the old man’s eye as a “vulture eye,” associating it with death, as vultures feed on carrion and circle the bodies of the dead or nearly so. It is his fear of the old man’s eye that compels the narrator to kill him, and the narrator explains that there is no other reason he wants the old man dead. It seems that the old man’s eye, likely clouded by cataracts—a disease associated with those who are old (and thus seem closer to death)—reminds the narrator of his own mortality, and so he must get rid of it. The fact that he listens to the deathwatch beetles in the wall—which, to the superstitious, means that someone is about to die—and that it is only the old man’s eye that compels him to commit murder provides evidence that he fears his own death as well as any reminders of it.
When the narrator goes to murder the old man, he hears a sound that he believes is the old man’s heartbeat. He says,
There came to my ears a low, dull, quick sound, such as a watch makes when enveloped in cotton.
It cannot be that he is hearing the beating of the old man’s heart from across the room, so he must be hearing his own heart. It is notable that he associates it with a watch, something that marks the passage of time and conveys the idea that time—and, by extension, life—is finite and limited. He hears this sound again after the old man is dead, and it becomes even clearer that the sound he hears is the beating of his own heart. His association of a heartbeat with a watch, something that keeps time, provides more evidence of his obsession with and fear of his mortality.