Hi @chaimdryzun1980, thanks for sharing the code. The technique and trigonometry for determining the pupillary distance looks OK. What kind of values are you getting and how much variance according to distance from eye tracker? Would be interesting to see a graph showing your PD in relation to ET distance. Indeed, there is expected to be some variance within tolerance so if you need a final value, it would seem reasonable to take an average value over a given time and space window.