Blue eyes are the result of a genetic mutation that occurred between 6,000 and 10,000 years ago. Originally, all humans had brown eyes, but a mutation in the OCA2 gene, regulated by the HERC2 gene, inhibited melanin production, leading to blue eyes. This makes blue the second most common eye color worldwide. Due to lower melanin levels, individuals with blue eyes are more sensitive to light, as melanin helps protect against UV and blue light damage. This increased sensitivity, known as photophobia, makes bright environments more uncomfortable for them.

Despite some drawbacks, blue-eyed individuals may have cognitive advantages. Professor Joanna Rowe from the University of Louisville suggested that they tend to be better strategic thinkers, though the exact reason remains unclear. Many renowned intellectuals, such as Stephen Hawking, Alexander Fleming, and Marie Curie, had blue eyes. Professor Hans Eiberg from the University of Copenhagen explained that all humans initially had brown eyes until a genetic “switch” altered melanin production. This discovery highlights how eye color diversity stems from genetic evolution, with blue-eyed individuals sharing a common ancestor.