A puzzle

Every so often, most likely on a taxi, I see a baby's shoe dangling from the rear bumper, I'm told this is to ward off the evil-eye. I've been looking this up because when the 'evil eye' is mentioned these days it tends to conjure up visions of wizards and witches and cauldrons and that didn't seem to fit the context. My undertanding from what I've found so far is that it's really to do with the harm you can do to yourself and others by being jealous. You look at something you like too long and hard and it adversely affects what you do and how you act and so impacts on others as well. I haven't found out where a baby's shoe comes into it.

If anyone can correct my understanding or explain the shoe...please let me know!