This document discusses visual impairment and blindness, and how guide dogs help the blind or visually impaired. It explains that some people's eyes have trouble functioning properly, causing visual impairment. It then outlines other senses blind and visually impaired people rely on. Guide dogs are described as the eyes for someone who is blind, and can help with tasks like crossing streets, going to stores, and avoiding obstacles. The document emphasizes that guide dogs wear harnesses so they can do their job of safely guiding their blind owners from place to place.