Hi,
You need to check for the light direction against the eye direction, and the steeper the angle the more "in your eyes"

then you also add in that equation the brightness of that light, and do a weighted average using all the lights you want to take in consideration.
you can use ArrayMaker to do this:
https://hutonggames.fogbugz.com/default.asp?W715store in an array, the lights that you want to affect your eye ( either you register them in editor, per level or per triggers).
then your eyes can go trhough that list and compute the lighting ( angle to light and strengths).
the other solution is to have your light responsible for trigger to your eye system when it's actually affecting the iris ( you work the other way around).
so when a light detected that your eyes is close enough ( trigger), you start computing the angle and when you reach certain thresholds, you fire an event to the eye to express the amount of exposure. you animate the iris based on that exposure amount.
Does that help?
bye,
Jean