Health and Medicine
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Babies’ eyes are still developing when they come into the world. In the first few months of life, their visual acuity and light perception will change, but what about color? It’s an often-repeated myth that all babies come into the world with blue eyes, but the truth is that eye color depends on genetics and a pigment called melanin.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.Are all babies born with blue eyes?
No, not all babies are born with blue eyes. In fact, research has found that more babies are born with brown eyes than blue. The Newborn Eye Screen Test (NEST) found that, of a sample of 192 newborns from a diverse cohort, 63 percent had brown eyes while just 20 percent had blue (the majority of which were white).
A baby’s eye color at birth is dictated by genetics, which is why siblings from blue-eyed parents are more likely to have the same eye color, but the same applies to green or brown too. According to World Atlas, Estonia and Finland are the blue-eyed capitals of the world, with 89 percent of the population having this eye color.
Do babies’ eyes change color?
Yes. In some countries, lots of babies are born with blue eyes – but this percentage isn’t reflected in the adult population. This is because a baby’s eye color can continue to change until around the age of two, reports Live Science.
When a baby is born with blue eyes that later turn green, hazel, or brown, it’s to do with how much melanin develops in a part of the eye called the iris. A lot of melanin will make brown eyes, less will create green or hazel, and a lack of melanin is what creates blue eyes. The science as to why is pretty cool.
Why are some eyes blue?
Nothing in the human eye is naturally blue, but people with no melanin in their iris have blue eyes – so where does it come from? Blue eye color is actually caused by the Tyndall Effect, a phenomenon similar to the visual trick that makes us perceive the sky as blue.
The iris is made up of two layers of cells: the stroma on top and the epithelium beneath. In blue eyes, the stroma is a translucent layer and contains zero pigment due to a genetic mutation.
When visible white light hits it, it scatters the light waves. Blue is scattered more than other colors because it travels as shorter waves, making the blue reflect most easily and making it more visible.
The stroma in brown eyes contains high levels of brown-to-black melanin, so this is the color we see. For grey eyes, it’s a similar phenomenon to blue, except the stroma contains more collagen. This makes the layer less translucent and dampens the blue.
The Tyndall effect still occurs in green eyes. However, the stroma contains small amounts of melanin that makes the blue reflection appear a different color.
Babies' eyes still have some ripening to do after they’re born before they’re ready to take in the big wide world, but did you know they come into it already with a taste for certain vegetables? Check out these hilarious ultrasounds of not-yet-born babies reacting to their mother eating carrot and kale.
All “explainer” articles are confirmed by fact checkers to be correct at time of publishing. Text, images, and links may be edited, removed, or added to at a later date to keep information current.
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