This product is called a "gentle leader". Yes it is very effective for the purpose your vet intends. I suggest you give it a try. Here is the website here in the US. And also do a google search on "gentle leader" it is sold on many webpages.
How it works......
http://www.premier.com/pages.cfm?id=17
The Gentle Leader® Headcollar is scientifically designed to work with a dog's natural instincts to respond to and obey his pack leader. Dogs don't speak human - they communicate with each other through body language, physical and vocal interaction. Because it applies pressure in the same manner and location as the pack leader or mother dog, Gentle Leader® helps you "speak your dog's own language," telling him both physically and psychologically that you are his leader!