Thanks Tim,

Reading through this, I am reminded of some research I did years ago using a home made pupillometer. I was seeing if the pupil responses were altered by posture. The subjects were allowed 20 minutes to relax and adapt to the dark so we could get a nice wide pupil of at least 6mm before I tested the light response.

For some, we could easily get a nice relaxed pupil, in others it was hard. I remember looking back over my results and it was quickly clear that the subjects who knew me best could easily relax their pupils and those who didn’t or were a bit suspicious were much harder.