A Seeing Eye Master

I have heard of a seeing eye dog... but never a seeing eye master!
As my 14 year old Shih Tzu continues to age his needs from me continue to grow.
He has had a cataract over his right eye for about five years now. His other eye has remained good, but it seems of late that his vision is deteriorating in that eye as well.
He bumps into the legs of t.v. trays, chair legs and has taken to barking at coats on the back of chairs thinking there is someone in the seat to give him a treat.
Earlier this spring he was having bad seizures and I thought when he banged into things he was just disoriented. Having got the seizures under control (for the most part) I have come to believe he is having trouble seeing well.
So when I am walking him I have found I have to be his eyes and use the leash to guide him on the path to wherever we are going. If not he is off the sidewalk and trying to walk on the slope of the ditches.
Once on the sidewalk, and kept on course, his nose leads him to the places other dogs have visited ahead of him (if you know what I mean).
He is still eager to go for walks, begs incessantly for treats and eats well. So if I have to be his seeing eye master I guess I will do so as long as he needs me.
After all he was the eyes and ears of my house for years, warning me when someone was at the door or in the yard.
–Until then,
Ken