Explain the following quote from "The Tell-Tale Heart": "It was open--wide, wide open--and I grew furious as I gazed upon it."

The quote you have identified is narrated to us by the
distinctly unreliable narrator who tells us the tale from his profoundly distorted point
of view. Having stolen into the old man's room with the specific intention of killing
him, and knowing that the old man is aware of the presence of some villain and is
terrified as a result, the narrator opens his lantern to reveal a narrow beam of light
which fell upon the "vulture eye" of the old man that the narrator is so obsessed
by.

What is important to note about the quote you have
identified is the response of the narrator to seeing the eye wide open. He grew
"furious" as he looked upon it, as it strikes him with fear and loathing and the sight,
we are told, "chilled the very marrow in my bones." The focus on the eye alone
emphasises the impact that it has on the narrator and the curious fascination that it is
able to exert over him.