He has a glass eye
due to him losing his eye as a child.
My ophthalmologist had him as a patient, and I've managed to hear the story of the havoc he played as a kid in school in Ossining, NY.
One day the school teacher had to leave the room, and assigned him to stand up front of the classroom and keep order in the class, and make sure nobody misbehaved.
Well, when she left, the class wouldn't listen to him and was just being plain rowdy. So, he took out his glass eye, and put it on the desk in front of all the kids. Instantly the room got quiet as he said, "I've got my Eye on you."
Nobody moved until she got back.