SaintFox: The only reason I can see for that transparency map is that it would allow one to change the texture maps for the iris and sclera independently of each other. That would be nice, but I'm not sure if it's really worth the effort. It might be better to simply use one material for each eyeball and one for each cornea or - in bagginsbill's version - "eye cover" and mix and match the scleras with the irises in Photoshop. I'd say the standard sclera will probably be fine for 95% of all renders, and if someone wants a different sclera texture, they'd probably need an special iris and pupil to go with it, anyway.

In any case, if we end up using bagginsbill's eyes, the transparency solution won't work, and the only way of changing the iris texture while keeping the sclera will be via masks.

-- I'm not mad at you, just Westphalian.