It takes a little time for the dog to get used to anything new when they've lost their vision, just like with a human. I used this on a foster Chihuahua "Bonita" when a cruel owner put chemicals in her eyes. She was blinded from that, and as far as I know it is permanent. Angels stepped up and got her one of these little harnesses with the wings and the "U" shaped guide around her face. She stood stock still at first but then I would leave it on her and she was soon going around the yard. At least she was not longer running into walls and so on. I would take it off when she would go into her crate for food, and at night when we would all be going to sleep. I totally love this and how it takes Accessibility to a new level for our companion animals. The device is very lightweight and did not encumber her mobility, it enhances mobility once the animal realizes it will protect them. I'd say she got used to the Halo in about 3 days. I actually ordered the SMALL, which fit the 7-8 lb chihuahua just fine. It is important to get all measurements as accurate as possible.