Perhaps the way the photons reflect through the iris is a way for human
beings to communicate information, (perhaps even faster than light, since
that would need to travel some meters, while photonic/quantum mechanical
changes could be more instant/local).
The photons are temporarely caught in the reflective mirrors of the iris.
Meanwhile these photons are manipulated everytime they reflect of of these
tiny mirrors.
This reflection is detectable in other people's irises and thus this might
be a way of transmitting large quantities of data.
Perhaps the entire DNA information is transferred in this way, so that
people can subcontiously know/detect if they like or dislike the other
person (perhaps physco information) /and/or if they would be a suitable
partner or not (dna information, more likely) ! ;) =D