When do babies' eyes change colour?

Want to know what to expect when it comes to baby's eye colour? Our guide, with expert advice from NHS GP Dr Philippa Kaye, covers everything from what colour your baby's eyes might be to why they could change colour after birth.

What colour eyes are babies born with?

When people talk about eye colour, they're referring to the colour of the iris, which is the part of the eye that surrounds the pupil. All babies will have black pupils and a white sclera (the main white part of the eye) unless they're suffering from jaundice, which can make the sclera appear yellow or conjunctivitis, which gives the eye a reddish or pink tinge.

You may have heard that all babies are born with blue eyes, but this is a myth. In fact, more babies are born with brown eyes than any other colour. Babies with dark skin and of African, African-American, Asian, and Hispanic descent are usually born with brown eyes, while babies with light skin may be born with brown, hazel, green, blue or greyish-coloured eyes.

Many babies are born with lighter eyes than they will eventually have as adults because of a lack of pigment and the fact that they have been inside a dark womb for 9 months and not exposed to direct light.

"The colour that your baby’s eyes are is due to the amount of melanin deposited in the iris," says NHS GP Dr Philippa Kaye. "The more melanin, the darker the eyes will be. Melanin is actually brown, but people with blue eyes have less melanin, meaning that more light can be reflected back so the eyes look lighter.

"How much melanin is deposited into the eyes depends on your genetics but also on light exposure. The cells which produce melanin respond to light and your baby will have been inside the dark womb for the previous nine months or so, meaning that with light exposure the eyes may change colour over time."

Why do babies’ eyes change colour?

Babies' eyes change colour due to the production of the protein melanin. Light exposure activates melanin production, so once a baby leaves the darkness of the womb and they are exposed to direct light melanin will start to change the colour of their eyes.

"If you are born with brown eyes these have lots of melanin already deposited and will stay brown," says Dr Philippa. "But if you are born with blue or grey eyes and more melanin is laid down in the iris once you are born, the eyes may change colour. The resulting colour depends on how much more melanin is deposited, from a little more meaning they stay blue, more leading to green or hazel eyes and even more melanin being deposited will lead to brown eyes."

When does a baby's eye colour stop changing?

"These changes in melanin take time and can vary between babies from a few months up to about 3 three years old, though often eyes have reached their final colour by the age of 1," says Dr Philippa.

Can you predict what colour eyes your baby will have?

Reach back into the far corners of your memory and you might recall a lesson in GCSE science class about genetics and how eye colour is determined. Thankfully Dr Philippa Kaye has given us a brief refresher: "Each parent donates a copy of each gene to the baby, meaning that every person has two copies of a gene for eye colour," she says.

"One copy can be dominant, and essentially hide the other, recessive copy. The gene for brown eyes is dominant over the blue eye gene. This means that whether you have one or two copies of the brown eye gene your eyes will be brown, but you could still be carrying a hidden blue eye gene. If you have blue eyes you must have two copies of the blue-eyed gene.

"Depending on what genes you and your partner carry, your children may have different coloured eyes. For example, even though you and your partner have brown eyes, if you are both carrying a hidden, recessive, blue eye gene, there is a 1 in 4 chance that you will both pass on this hidden gene and your baby will have blue eyes. Or if you pass on even one copy of a brown-eyed gene, your baby’s eyes will be brown, though they themselves could pass on that hidden blue-eye gene for many generations."

Bearing in mind these hidden recessive genes, it's very difficult to actually predict what eye colour your baby will have because two brown-eyed people could be carrying blue-eyed genes and pass them on to their child. There is one situation where you can predict your baby's eye colour though: "If both you and your partner have blue eyes, then you can only pass on blue eye genes, so your child’s eyes are likely to be blue!" says Dr Philippa. "Brown is the most common eye colour across the world, but in Northern Europe where it is colder, blue eyes are more common."

When should you go to the doctor about a baby's eye colour?

"Sometimes babies can have eyes that are different colours or have patches of different colours, called heterochromia," says Dr Philippa. "This can occur as a variation, but can also be related to other health conditions. If you notice this please discuss with your doctor.

"Your baby will have a medical check at birth and at six weeks and the health care professional will look at their eyes. In particular, they will shine a light into your baby’s eyes to look for what is known as the red reflex, as they try to look into the back of your baby’s eyes. If this isn’t present and looks white then you will be referred to a specialist.

"If you have any concerns about your baby’s eyes, from a squint to a change in colour of the sclera (the white of the eye), then please seek medical advice."

Are there any common eye conditions that present at birth?

While you're marvelling at your baby's beautiful newborn eyes you might pick up on other aspects of the eye that concern you. "There are some conditions in the eye which can be picked up at birth and others which can develop relatively quickly, such as jaundice, in which the white of the eye may look yellow," says Dr Philippa. "Babies can have conditions such as cataracts, or issues relating to the eye related to being born prematurely. If you have any concerns about your baby’s eyes or vision please speak to your doctor."

Pics: Getty Images

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