What would make an older child's eye turn inward?!

I have a friend who is in the hospital right now and has seen 3 eye doctors and they are all stumped. The eyeball itself is normal and strong. Her right eye began turning inward a few days ago. When she is tired it gets worse.. to the point that you cannot see any conjuctiva on the inner surface. It seems as if there was a House episode that depicted a similar case. But anyhow, would there be a type of tumor that would cause this? We has theorized possibly a virus that had positioned itself in that area. They are running MRI, CT, and possibly a spinal. Any suggestions would be appreciated.