If you have blue eyes, your family is much bigger than you think. Approximately all blue-eyed people on Earth are your relatives. Indeed , researchers have discovered that those with this trait descend from a single ancestor . He or she lived around 6,000 years ago , so it’s unlikely you have an extra uncle. Below, all the other curiosities about who has blue eyes.
All for a “mistake”. Blue eyes are the result of a genetic mutation. Researchers from the Department of Cellular and Molecular Medicine at the University of Copenhagen found that before the person with the mutation appeared, everyone had brown eyes. The “error” is found on the OCA2 gene, which acts on the color of the skin and eyes: the effect of the mutation is to “turn off” part of the gene, making the iris appear clear. Only 17% of the population has blue eyes , compared to 55% of people with brown eyes.
Sensitivity to light. People with light eyes are often hypersensitive to light. This is because light eye lacks melanin in the iris, a compound that protects the eyes from damage from bright light.
Night View. On the other hand, light-colored eyes can see better in the dark, because the absence of melanin allows more light to enter the eye, even when the brightness of the environment is almost zero.
Red eyes . The problem with those who have light eyes is that in the photo they will come with strange red eyes. This happens due to the increased amount of light entering the clear iris. Red-eye occurs when light is bounced back towards the lens.
Pain tolerance. One study found that blue-eyed women had better pain tolerance. For example, during childbirth, brown-eyed women tend to experience less pain than those with brown eyes.
Waardenburg syndrome. One reason a black person may have blue eyes is Waardenburg syndrome. This pathology is associated with various pigmentation disorders and occurs concomitantly with deafness.
Sources:
https://link.springer.com/article/10.1007%2Fs00439-007-0460-x
https://www.huffingtonpost.co.uk/2014/08/14/how-your-eye-colour-can-effect-your-health_n_7328078.html