Special ground procedures aren't required when the RVR is 1200 ft or above, other than things like ILS protection areas.
The FAA did some studies which concluded that (on the ground) pilots can navigate visually just fine down to something like RVR 500 ft. So LVO level 1 is defined as RVR between 600 and 1200 ft (exclusive). Below RVR 600 ft other restrictions come into play.
By the way this is the same in Canada. LVOP is mandatory for operations below 1200 ft RVR. At or above 1200 ft, a Reduced Visibility Operations Plan (RVOP) is recommended but not mandatory.