We are now familiar with dogs helping people with sight loss but where did the idea come from? And how have the ways of selecting, training and using guide dogs changed over time?

Bridget Kendall explores the history of guide dogs with Pieter van Niekerk, Head of Public Relations for the South African Guide-Dogs Association and with Karin Floesser, one of the guide dog leaders of the German Federation for the Blind and Partially Sighted. Bridget is also joined by journalist and educator Miriam Ascarelli, biographer of Dorothy Harrison Eustis, the philanthropist who in the 1920s co-founded the American Seeing Eye school, and she hears from Michael Hingson, a blind survivor of the 9/11 attacks.

(Image: A guide dog in Shanghai, China. Credit: Wang He/Getty Images)