I have 22 adult quail, and the same thing is happening to several of their eyes. A couple of them are completely blind, and others only have one eye affected. We haven't lost of them yet. Did you ever find out what this was from? I would like to treat as soon as possible.
Those are the "clusters" I've been finding on one of our Cinnamon Queen's eggs this last week. It's almost like sand got wet and stuck to something, because I can just wipe them off with the pad of my finger without any damage to the shell itself. There were several clusters on each of her eggs...