It's always interesting to me when I hear people say this, because I can't understand it at all. If you ask me to close my eyes and visualize a car, I don't actually see anything. I can recall what a car or a specific car looks like, but I don't actually "see" it in any sense. Same with reading - I don't (can't) actually visualize the characters, settings, etc. I'm always momentarily confused when someone complains about a film/TV adaptation with "such and such actor is really good, but that character is supposed to have GREEN eyes!". To me it's an incidental fact, whereas to some people it's central to their conception of the character (as if a real-life person had suddenly changed eye color for no apparent reason).
I've always wondered whether my condition is the norm, or if most people are capable of visual recall.