I still have a hard time believing this is actually real. I also don't see how you actually could do many jobs with this condition. At least I couldn't imagine doing any job I ever head without the ability to manipulate visual information in my head.
When I solve an imaginary logic problem such as advancing the hands on a clock I can't see the before and after states but I can infer their positions by the directions they must point and then read the new time from that.