I had a patient in the ER once that was on meth and pulled his own eye out. Yep, thought there was a bug behind it so he dug it out with his fingers. The paramedics found it in the bottom of a sink that was 1/3 of the way full of blood. It still had the optic nerve attached. You should have seen the look on their faces as they come in through the door with this guy who has his face all bandaged up and a human eyeball in a specimen cup. One of the most interesting things I've seen yet.
But as far as it actually just "falling out" without any trauma? Highly unlikely.