Okay, I did some measurements on Antonia, but apparently I suck at Googling, because I couldn't find any source for average head length and width in humans, let alone caucasion females. :(

Anyway based on equating a Poser unit to 96 inches as bagginsbill suggested, Antonia's head would be 8.88 inches (22.55 cm) high from top of cranium to chin and 6.05 inches (15.36 cm) wide. That's about an inch shorter and narrower than my head, which seems about right. But if someone can find some actual stats, that would be quite welcome. Her eye distance, measured between the centers of the eyeballs, is 64.4 mm, which is pretty close to the average that SaintFox cited. The distance between the centers of the pupils is of course a bit larger. Being close to the average is a good thing for an all-purpose figure, so I'm quite happy with that.

So I think it's save to say that in proportion to the head, the irises and cornea are indeed of the correct size, which means that the eyeballs need to be made smaller in relation. I'll have a go at that with Antonia's existing eyes to see if there needs to be something changed about the shape of the lids.

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