I found this news story from last year - an interview with a woman about living with Prosopagnosia. There was a pertinent quote by the woman, Kathy, who was the subject of the story:
"Kathy says it's not that her vision is blurry, but instead faces are no more unique to her than hands are to us."
Now that I have started telling a few people about my Prosopagnosia, I am always looking for a way to explain it to people, and this is one of the better ones I have come across. We have all looked at people's hands, seen them, and then forgotten what they looked like once we walked away. Most people would be hard pressed to recognize someone else by hands alone.