There is a bug in poser 7 and poserpro (and below) with the refraction node, Instead of bending the lightray back as it supposed to do, it bends in the opposite direction, so it accumulates the effect instead neutralizing it. I believe it's fixed in poser 8, but I'm not sure. I spoke it with Baggingsbill about this some months ago, and I made a fix: see picture.

best regards,

Bopper.

-How can you improve things when you don't make mistakes?