Does your screen go black when you open Tobii Experience, Tobii Ghost, or enable Gaze Trace in the Tobii Core software?
This can happen if something has gone wrong with your graphics drivers. Install the latest drivers from your manufacturer and check if there is an option to Perform a clean installation.
It is usually found under the Advanced installation option.
To temporarily get out from the black screen you can sometimes Alt+Tab to give focus to another window.