All blue eyed humans are descended from a single common ancestor, almost certainly male, almost certainly living in what is today Romania 6,000 to 10,000 years ago who happened to be born with a defect in his melanin producing gene. This benin mutation had a curious side affect, blue eyes.
So what if this mutant freak was never born, or failed to reproduce?
How would that have affected the development of human culture and human history?