@00:28There are balls made with Masilla Epoxi (some kind of clay that it make hard in ten minutes), and paint it white. They have a small hole for pupil and you can move the eye help by a toothpick. And simple!
I have it to tweaked the contrast too much for show it here, and the compressor kinda messed up some things. If you want, you can see it more properly here (somekind of official page): [link]
I made this short with a friend, in the last months of 2009. Shot with a regular webcam. Yes, we fucked it from the begining, but we learn a lot about the whole process of making a stop motion animated film, from the scratch. Maybe, later, i will up the animatic.
The music in the credits is from Mozart. Played by the Vienna Philharmonic Orchestra: [link]
Of course, medical advances have pretty much killed this practice...