Quote - I've stared at my colleagues' eyes over lunch, and I think unless we can get actual refraction of the light entering the cornea - does Poser do that? I'm clueless - we'll need to make the iris somewhat concave to mimic the way it catches the light. Not dish-shaped like they are now, but uniformly concave. Without diffraction, a convex shape is definitely not going to produce the correct image.

Also, like cobaltdream said, the iris needs to be set back a little to catch a shadow at the edges.

My $0.02,

To be honest, I'm not sure what would be best for Poser. The eye I used in that render I posted was yours, from Antonia, and the only thing I did to it was subpatch it to make it smoother. I think the iris turned out the best of all, and that was with the shape you designed. It had a healthy dose of bump and some SSS and refraction working on it though.

For my part, I'm not in this to try to design a new eye for Antonia, but just for the technical challenge to see if my ideas work.
I'll leave it up to you guys to argue about what works best for Antonia and Poser.  ;-)