Quote - Thalek: Go figure. Your thought about the iris texture had occurred to me earlier but I had dismissed it. But your comment prompted me to see what would happen if I expanded the iris (gave it a different colour map from the rest of the eye parts). And the white circle around the edge seems to have disappeared.

Still doesn't make total sense to me, since in theory the way Antonia's eye UVs are laid out, I would have thought I'd see sclera there, not just blank white. But the main thing is that it seems to be working now.

Glad to have been of assistance, even accidentally.

I'm too tired to understand rjjack's explanation, so I'll read it again tomorrow.  But aren't over-lapping material zones frowned upon?