A few days before his proctological exam, a one eyed man accidentally
swallowed his glass eye. He was worried for a while, but there were no
ill effects, so he forgot about it.

Once he was in the doctor's office, the man followed instructions,
undressed, and bent over. The first thing the proctologist saw when he
looked up the man's arse was that eye staring right back at him.
"You know, " said the doctor, "you really have to learn to trust me."