>>2887110In case anyone still cares, I made it work by
1. removing the texture with faux specular reflections from the cornea material
2. creating a custom ray material for the pupil, which has the prior cornea texture as ALBEDO_SUB_MAP_FILE
3. Setting the now blank cornea to glass material
(actually I needed to separate the left and right eye materials, and create separate pupil materials, because the cornea texture UV needs to be flipped for one but not the other...)
