thanks! it's getting alot closer... this:

openframeworks.cc/forum/viewtopic.php?f=9&t=2336&hilit=GSL

proved to be a really helpful for calibration.

Aha, that post makes more sense now :)

You could also try using the camera calibration portions of OpenCV... but then again, the kind of distortion you're getting is probably much different than lens distortion (and it would be a pain to supply it with the necessary amount of training data).

Again, great to see this working so well :) I hope as much of this as possible will be released once you're done. There's always space for more DIY eye tracking software + hardware!