So this is my first time really messing around with Iray, despite having owned it for a few months. I did a render of a model and this is how the model looks in the CC3 viewport:
Notice that her eyes are PURPLE. 
This is how she looks in the Iray Preview window:
 And her eyes are now blue.
Why did her eyes change color?? I mean Iray does make the model look different - in a GOOD way - but the eye color is weird. I want her eyes to be purple.