I'm just learning a bit about this myself, but I figured I could maybe point you in a direction!
My new rabbit does something called "scanning". Apparently, this is a sign of bad eyesight. My rabbit just looks like she's drifting her head back and forth. Initially, I was concerned that it was the start of head tilt or that she had some loss of motor control, but it turned out just to be this scanning. She only does it when she's sitting still or laying down. They compared this behavior with bringing a newspaper closer then farther away to bring it into focus. She is similarly turning her head till she brings things in focus.
Other than that, I have no idea. This is a really interesting read though if you have time:
http://www.bio.miami.edu/hare/vision.html
I'll be interested to read this thread and see what everyone else has to say!