I did a quick scan through google scholar and some science publications, and it seems to me that, unlike with skin pigmentation, the science with regard to selective pressures on eye color is still in its infancy. It certainly isn't totally clear that it has to do with light eyes being more adaptive in low sun areas, although there are certainly some studies which suggest that and continuing research may bring some light to bear on the issue.
(I don't know why, btw, a Duke University study would be assumed to be invalid.)
See this study for some background on iris pigmentation. It seems just from the description of the various parts of the iris and their function that research into the impact of iris color in reflecting some of the light, and differences in contraction time might be fruitful areas of research, but that's a layperson's view so perhaps I'm reading it incorrectly.
http://bashaar.org.il/files/4150.pdf
They mentioned several factors that were new to me, like the possible effect of eye color on reaction time and certain sports. They also cited other literature to the effect that the ability to overcome seasonal affective disorder (SAD), a major depressive disorder, is linked to lighter eye color.
As for the influence of sexual selection, that has always seemed problematic to me because it is so subject to changes in culture. Obviously, if a group rises to power which carries a certain phenotype, that phenotype might and probably will become preferred and there will be sexual selection for it.
However, I don't know how sound it is to transfer these types of judgements as to "attractiveness" 15,000 years into the past to other very foreign cultures. Certainly, even in more modern times, children born with blue eyes in remote African tribes were sometimes killed at birth for being "alien". (That's of course before the total impact of colonialism, which introduced the idea that fair pigmentation is associated with privilege.)
Among groups which normally are lighter eyed and haired at birth and sometimes into youth, I could see, however, where males might be more attracted to females who carry those traits for longer because it might have associations with infantilism and therefore malleability.