I have a 180# Great Dane with k9 diabetes. One day, he was fine at his 5 o'clock feeding. Four hours later, he was whimpering and running into the furniture. I looked into his eyes, and new he was blind. The next morning I was at the vet when they opened up. After some tests, it was found out that he had severe diabetes and hypo thyroid. I have to give him two injections of insulin a day, and he is on a special diet, which I have to sprinkle a teaspoon of powdered fiber on. He's become quite an 'attachment' dog since going blind. He always has to follow me around and likes to sit close enough to be touching me when I'm watching tv. Wal Mart has the insulin and syringes at a very fair price compared to other places.
Make sure you find a vet that knows about k9 diabetes well. I went through three vets before I found one that I felt knew what he was talking about. Two others just wanted to keep running highly expensive tests, and I felt they weren't helping him in any way.
K9 diabetes is very common. It's a little tough to get used to at the beginning with the few added responsibilities, but it becomes part of your daily routine. Everyone's dog is different, so take the horror stories you read online (I spent days reading about it on line when I first discovered my dog had it), with a grain of salt. Find a competent vet, and follow his instructions.
Please pm me and let me know how your dog is doing when you find out more.