Author and neurologist Oliver Sacks has prosopagnosia (face blindness) and he wrote about it in The New Yorker. The article isn't online, but here's an audio interview with him.
From The New Yorker's abstract of the article:
Severe congenital prosopagnosia is estimated to affect two to two and a half per cent of the population–six to eight million people in the United States alone.
Writer describes his own difficulties recognizing and remembering faces. He also has the same difficulty with places and often becomes lost when he strays from familiar routes. At the age of seventy-seven, despite a lifetime of trying to compensate, he has no less trouble with faces and places than when he was younger. He is particularly thrown when seeing a person out of context, even if he was with that person five minutes before. Writer gives several examples of his inability to recognize familiar people out of context, including his therapist and his assistant.
