How Rare Are Grey Eyes?
Eye color might be more aptly referred to as iris color. What gives the iris its unique coloring is the degree to which melanin is present (via All About Vision). Melanin is a brown pigment that dictates both our skin and hair color. Those with darker eye colors, such as brown, have more melanin present than those with lighter eyes such as blue or hazel. According to World Atlas, anywhere from 70-80% of people worldwide have brown eyes. Global prevalence rates of lighter eye colors, such as green, amber, or blue, are much smaller, falling between 2-10%.
Even smaller are prevalence rates of more unique eye colors, such as red, violet, and grey (via World Atlas). Grey eyes were not always acknowledged as their own distinct category of eye color, however. For years, those with grey eyes were often lumped in with blue-eyed individuals (via Verywell Health). Now, scientists believe that grey eyes differ significantly from blue eyes due to their lower levels of melanin. Rather than containing melanin in both the front and back layers of the eye, those with grey eyes only contain melanin in the back layer, according to All About Vision. The connective band of tissue between these 2 layers is called the stroma, and it is thought to disperse light differently, thereby reflecting shades of grey.
Benefits and personality traits of people with grey eyes
Less than 1% of people are believed to have grey eyes, making it an incredibly rare eye color, predominantly found in Europe (via Healthline). While genetics are thought to play a role in whether or not a person possesses grey eyes, science tells us that it's far more complex than simply whether a gene is dominant or recessive (via All About Vision). In fact, according to the Vision Center, there are thought to be 16 or more different genes responsible for eye color.
One health benefit found to be associated with grey eyes is that these individuals have a lower risk of developing certain skin conditions related to type 1 diabetes, lupus, and thyroid disease (via All About Vision). Additionally, research has shown people with grey eyes to be more competitive and strategic when it comes to activities, such as long-distance running, golf, and studying (via Vision Center).
On the flip side, however, those with grey eyes may be more susceptible to ocular melanoma and light sensitivity than those with darker eye colors (via All About Vision). Therefore, it's important for people with grey eyes to wear protective sunglasses while outside.