Edgar Allen Poe's short story "The Tell Tale Heart" is told from the first person point of view by an unknown narrator who seems obsessed with an old man's eye. It is actually the story of a murder told from the point of view of the deranged murderer.
The narrator spends much of his time trying to convince the reader that he is not insane. This person lives with an old man who evidently has a cataract over his eye, and the narrator becomes obsessed with it to the point of thinking it to be evil. He finally kills the old man and is proud of his ability to cover up his crime. His paranoia finally gets the best of him, though, as he begins to think the police can hear the man's beating heart, and he confesses what he has done.