Unheard of diseases are always the worst. I did all sorts of research before buying my GSD and thought I was such a good new owner. I get my puppy home and noticed his eyes seemed to water a lot. I thought it was because of the dust in the air and ignored it, its always dusty here. Almost a year...
I've heard of this, ever since then I've refused to let my dogs near pools of water. I am SO heartbroken for you, I'm very very sorry. Sending lots of hugs your way.