No different categories for T/O! Below a RVR (runway visual range) of 400m, so called "low visibility operations" must be in progress and broadcasted by the airport.
Depending on the aircraft you operate, certain regulations have to be met which equipment must be available, who performs the takeoff-run and so on.
If you meet all the restrictions, you can legally takeoff!
The 737 classics, for example (without head-up guidance), are able to take off with a RVR as low a 125 meters.
Flexi