For the HMD eye tracker, the calibration points effectively define a bounding box for the 2D screen area beyond which POR data may not be trustworthy. Depending on the application, you may need to determine fixations.
Latest research suggests that a velocity-based approach gives good results.
Fixations are significantly slower then saccades. When the tracker is in reset mode, nothing happens. When in run mode, your code will need to display the scene that you're testing, and weill need to copy the coordinates to a dynamic data structure for later storage.