![]() ![]() When you think of someone who enjoys a drink, their eye colour probably isn’t the first thing that comes to mind. ![]() People with light eyes are also more likely to develop optical melanomas, due to having less pigment in their eyes to absorb UV rays, while people with darker eyes have more melanin to shield their eyes from sun damage. Skin cancer usually develops from moles, often stemming from too much sun exposure. This links to melanoma risk too, as light eyes are connected to a person’s likelihood of developing moles. Darker irises block more UV rays, potentially leading to lower risks for AMD (1). Since lighter eyes – such as blue, green and grey – have less melanin in them, they are more susceptible to sun damage. However, AMD is also brought on by too much exposure to ultraviolet light. AMD is also more common in Caucasians – who are more likely to have blue eyes – so some experts suggest that the association between AMD and eye colour could actually be down to race, rather than just eye colour as initially thought. Studies have been conducted on the connections between eye colour and the development of AMD, and it has been found that having light eyes can almost double your risk of developing AMD. It is when your central vision begins to deteriorate, beginning as blurriness before progressing to blank spots. Pigment levels can also fluctuate after childhood, so the eye colour you have in twenty years’ time might not be exactly the same as you have now!Īge-related macular degeneration (AMD) is one of the leading causes of sight loss in the UK. This is because human eyes don’t have their full amount of pigment at birth, resulting in temporarily blue eyes. Eye colour can also change over the course of someone’s life, with many babies being born with blue eyes which gradually darken over the coming months or years to become brown. Globally, however, brown eyes make up 90% of the population, blue eyes 8%, and green eyes a tiny 2%. This is followed by green eyes at 30%, with a mere 22% of the British population having brown eyes. While blue eyes used to be the least common colour and were seen as a rarity, 48% of the British population now have blue eyes. As eye colour depends on the amount of pigment in the iris (lots of pigment results in brown eyes, while less pigment results in lighter eyes), this mutation limits the production of melanin in the iris. ![]() The science behind this is particularly interesting, with researchers suggesting that a genetic mutation in Europe between 6,000 and 10,000 years ago led to the development of blue eyes. One of the most widely-discussed ideas around eye colour is that all blue eyed people have descended from a single common ancestor. It’s hard to predict what eye colour your child might end up with, as even one sibling’s eyes can differ dramatically from the next sibling. It’s simply an indicator that “nature is constantly shuffling the human genome, creating a genetic cocktail of human chromosomes and trying out different changes as it does so.Eye colour is a funny, unpredictable thing and is influenced by up to 16 different genes. If all of you brown-eyed girls out there are feeling a bit bummed that you don’t share a bond like blue-eyed people, don’t worry: Having blue eyes is not a positive or negative thing, Eiberg says. “They have all inherited the same switch at exactly the same spot in their DNA.” “From this we can conclude that all blue-eyed individuals are linked to the same ancestor,” Eiberg said. However, while there is a large range of melanin levels in people with brown eyes, people with blue eyes all have relatively the same levels of melanin. So what was it in his research that led Eiberg and his team to conclude that all people with blue eyes are related? Melanin levels can vary a lot from person to person that’s why there are so many different eye colors. The result is that melanin could be “diluted” to produce blue eyes instead of brown. While the mutation did not allow the gene to completely “switch” off our melanin production (if that occurred, albinism would be the result), it did reduce the amount of melanin produced. A mutation in the OCA2 gene, Eiberg says, allowed the body to essentially turn off or reduce the gene’s ability to produce melanin - the pigment that gives our hair, skin, and eyes their color. ![]()
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