z coordinate of eye position

Does the SDK not clearly provide a z coordinate for eye position (distance of user's pupil from tracker)
We have gazedata.lefteye.pcenter.x, and gazedata.lefteye.pcenter.y, but no Z coordinate. Tobii gives distance of pupils, eye tribe must as well.
We have gazedata.lefteye.pcenter.x, and gazedata.lefteye.pcenter.y, but no Z coordinate. Tobii gives distance of pupils, eye tribe must as well.