A chap I see quite often in the park has two Dachshunds, one about 5 years old, the other about 14. The older one is blind, but he brings them both to the park, lets the young one run around to her heart's content, carries the old lady a few yards into the park proper and lets her sniff around for a while then returns her to the car. Apparently she gets around indoors without any problems and knows exactly when it is meal times!
Mike