A couple of days ago on Flickr, I came across this picture and was astonished, having never before heard of guide-ponies. I researched the subject and found this very interesting material concerning the Guide Horse Foundation.
Our mission is to provide a safe, cost-effective and reliable mobility alternative for visually impaired people. The Guide Horse Foundation is committed to delivering Guide Horses at no cost to the blind, relying on un-paid volunteers and charitable donations to pay all travel and housing expenses for the blind handler’s on-site training.
The Guide Horse Foundation was founded in 1999 as an experimental program to access the abilities of miniature horses as assistance animals. There is a critical shortage of guide animals for the blind and guide horses are an appropriate assistance animal for thousands of visually impaired people in the USA.
In early experiments, Guide Horses have shown great promise as a mobility option, and people who have tried Guide Horses report that the Guide Horses perform exceptionally well at keeping their person safe. These friendly horses provide an experimental alternative mobility option for blind people. People who have tried Guide Horses report that the horses demonstrate excellent judgment and are not easily distracted by crowds and people.
There is more material here.
There are lots of pictures and more information in the link I provided. Please take a look.