i had a great shepard and he ended up devolping a problem with his eyes. we toke him to many vets and even a collage and they said the problem he had was his tear ducts quit working. poor guy ended up going blind.he got to the point where he could not even move around without running into everything. i was gone in the military and my parent had to put him down. i have asked around and know one every heard of it. let me know what everyone thinks