I just saw a segement on a local technology show ( Beyond Tomorrow - Australia) where some researchers were creating devices that "Knew" when you were looking at them. They used a CCD camera surrounded by IR LED Diodes.
The camera detected the Red-Eye reflection from the users eyes to determine if they were looking at the camera.
This system sound like a lot like the Track IR. It may be a good way to remove the need for the reflective dots.