Milestones & myths

Why a baby's eye colour changes in the first year

The grey-blue eyes in the hospital photo are not always the eyes your child keeps. Pigment is still arriving in the iris, and it can keep arriving for months. Here is the typical timeline, and the handful of signs that are something else entirely.

by Dr Chan Li Yen · MBBS, MOphth (UM), Fellowship in Paediatric Ophthalmology & Strabismus

Practises at Hospital Kuala Lumpur 12 min read · 2,185 words

Key takeaways

Most babies are close to their lasting eye colour by around nine months old, with a smaller amount of drift possible out to age three.
The colour change happens because melanin production in the iris ramps up after birth, not because the eye itself changes structure.
Babies born with more melanin already in the iris, which includes most Asian, Hispanic and Black babies, start darker and have less visible change ahead of them.
Eye colour is polygenic, shaped by at least ten genes working together, so it can often be guessed from the parents' colouring but never predicted with certainty.
A lasting difference between the two eyes, a hazy or enlarging eye, a recurring white glow in photos, or a very pale iris with light sensitivity or wobbly eyes are separate signs, not ordinary colour settling.

The grey-blue eyes in the hospital photo are not always the eyes your child keeps. In most babies, pigment is still arriving in the iris after birth, and it can keep arriving for months. This is one of the most reliable pieces of newborn folklore that turns out to be broadly true, with a few details worth getting right.

When do a baby's eyes actually change colour?

Mostly in the first nine months. The American Academy of Ophthalmology puts it plainly: an infant's eyes "may look more blue-grey" in the early months "and then get darker as eye pigment develops," with most babies settled into the colour they will keep for life by around nine months old. Other sources place the fastest movement a little later, around six to twelve months, with a smaller amount of drift still possible out to age three in a minority of children. None of these figures is a fixed appointment on a calendar. Some eyes are essentially finished by four months. Others are still visibly shifting at the first birthday. Both are normal.

Why does the colour change at all?

Because of melanin, the same pigment behind hair and skin colour, and where it sits inside the eye. The iris, the coloured ring around the pupil, has a front layer called the stroma, and pigment cells called melanocytes are scattered through it. Those melanocytes are present from birth but have made very little melanin before delivery. After birth they ramp up production, on roughly the same schedule as the pigment cells in skin and hair. More melanin in the stroma means a darker eye. Very little melanin means a paler one, and pale eyes look blue not because there is any blue pigment there at all, but because of the way light scatters off a stroma with little pigment in it, the same physics that makes the sky blue. A newborn's grey-blue eyes are, in that sense, a preview of an unfinished picture rather than a false one.

What is the typical range, and when should I stop expecting change?

By around nine months, most babies are close to their lasting eye colour, and by age three the picture is essentially complete for almost everyone. A newborn eye screening study of 192 babies found brown the most common birth colour overall, at 63%, with blue at around 21% and green or hazel making up the rest. The same study, drawing on earlier twin research, notes that roughly 10 to 20% of children go on to show a further colour change between three months and six years of age, which is worth knowing if your child's eyes seem to be settling on a slightly different shade at eighteen months than they showed at six. A little further drift within that range is ordinary, not a sign that something has gone wrong the first time round.

Why do most Asian babies' eyes start dark and stay dark?

Because they are usually born with more melanin already present in the iris, so there is less room left for the colour to move. In that same newborn study, babies identified by their parents as Asian were 80% brown-eyed and only about 2% blue-eyed at birth, a pattern echoed in Hispanic and Latino infants and in Black infants, all of whom were far more likely to be born brown-eyed than white or Caucasian infants, who were closer to an even split between blue and brown. A baby born with a deep brown iris already has a stroma dense with melanin, so the same after-birth pigment surge that turns a pale newborn eye green, hazel or brown has much less visible work left to do. The eyes are still finishing the same biological process. There is simply less distance left to travel.

Is eye colour just genetics, and can we predict it?

Genetics, yes. Simple, no, whatever you were taught about brown being dominant over blue in a school diagram. As the US National Library of Medicine's genetics reference puts it, "the inheritance of eye color is more complex than originally suspected because multiple genes are involved." Two genes on chromosome 15, called OCA2 and HERC2, do most of the work between them, one making the protein that helps melanocytes build and store melanin, the other switching that gene on or off. At least eight further genes make smaller contributions on top. The old single-gene, brown-dominant model "was too simplistic," and the honest position is that a child's eye colour can often be guessed from the parents' colouring, but genuinely cannot be predicted with certainty, because the trait is polygenic rather than a straightforward inheritance of one parent's colour over the other's.

What if one eye looks a different colour from the other?

Worth a proper look rather than a photo comparison. Flash photography can make a baby's eyes look mismatched in a single picture even when they are not, especially in the first year while the true colour is still settling, so check in daylight over a few days before assuming anything. If the difference is genuinely there in ordinary light, and stays there, that is heterochromia, and I have set out the honest line between the harmless kind and the kind that needs an appointment in two different coloured eyes: when it is just genetics and when it is a same-day referral. This article is about the ordinary, whole-eye colour settling every baby goes through. A difference between the two eyes is a separate question, and that other article is where to take it.

What changes are not just colour settling in?

A few, and they matter enough to name clearly rather than leave buried in a general reassurance. A cloudy, hazy or grey look to the clear front window of the eye, or one eye that looks larger than the other or larger than it did last month, is not a colour change at all. It can be a sign of childhood glaucoma, and I have set out why in big, beautiful eyes can be a warning sign: congenital glaucoma, which is worth reading today if that description fits your baby rather than waiting to see if it settles. A white or pale glow in the centre of the eye in flash photographs, rather than the usual red-eye colour, is a different sign again, called leukocoria, and most of the time it is nothing, but a glow that keeps reappearing across different photos deserves the same-day look I describe in the white glow in a photo, and three other signs to know. Neither of these is the ordinary iris pigmentation this article covers, and neither should be watched and waited on the strength of what you have just read here.

What about a very pale iris with light sensitivity or wobbly eyes?

That combination points somewhere else entirely, and is worth naming plainly. Albinism is a hereditary condition, caused by gene changes passed down from parents, in which the body makes very little of the melanin that would otherwise darken the iris, and melanin also matters for how the retina and optic nerve develop, not only for colour. Babies with albinism typically have a strikingly pale iris that lets stray light through rather than screening it out, real sensitivity to ordinary daylight, and often nystagmus, the rapid, uncontrolled eye movement I cover fully in wobbly eyes in a baby: nystagmus. A baby with pale but otherwise settling eyes and no light sensitivity or wobble is very unlikely to have this. A baby with all three together is worth an eye doctor's appointment specifically for that combination, not just a general check.

A newborn's grey-blue eyes are usually an unfinished picture, not a false one.

So what should I actually watch for, month to month?

Very little, for most babies. If your child's eyes are gradually shifting shade over the first year, in either direction, that is the ordinary process this whole article describes, and no action is needed beyond noticing it and, if you enjoy that sort of thing, taking a photo every few months to watch it happen. What deserves a proper look is any of the specific, separate signs above: a lasting difference between the two eyes, a hazy or enlarging eye, a white glow that keeps recurring in photos, or a very pale iris paired with light sensitivity or wobbly eyes. None of those is the colour settling in. All of them are worth naming to your child's doctor by name rather than waiting to see if the picture becomes clearer on its own, because with each of them, being seen earlier is what actually changes the outcome.

This is something else, not colour settling in, if…

One eye stays a genuinely different colour from the other in ordinary daylight over several days, not just in a single flash photo.
The clear front of the eye looks cloudy, hazy or grey, or one eye looks larger than the other or larger than it did last month.
A white or pale glow keeps appearing in the pupil in flash photographs, in more than one picture.
The iris is very pale and comes with real sensitivity to ordinary daylight, or with rapid, wobbly eye movements.

Common questions

When do babies' eyes change colour?

Mostly within the first nine months. Pigment cells in the iris make very little melanin before birth, then ramp up production afterwards, with most babies close to their lasting colour by around nine months old. A smaller amount of further drift is possible for some children out to around age three, so an eye that still looks slightly unsettled at eighteen months is not unusual.

Why do babies' eyes look blue-grey at birth even when they end up brown?

Because there is very little melanin in the iris yet, and a stroma with little pigment scatters light in a way that looks blue, the same physics that makes the sky blue. There is no blue pigment involved at all. As melanin builds up after birth, that scattering effect fades and the true, more pigmented colour shows through.

Why do most Asian babies' eyes start dark and change so little?

Because they are usually born with substantially more melanin already present in the iris than lighter-eyed babies. A newborn eye colour study found around 80% of babies identified as Asian were born brown-eyed, against roughly an even split between blue and brown for white or Caucasian babies. With more pigment already there at birth, the same after-birth melanin surge has much less visible distance left to move the colour.

Is eye colour determined by simple genetics, brown dominant over blue?

No, and that classroom model is outdated. Eye colour is polygenic, shaped mainly by two genes on chromosome 15, OCA2 and HERC2, with at least eight further genes making smaller contributions. A child's eye colour can often be guessed from the parents' colouring, but genuine surprises happen, because no single gene simply switches the outcome one way or the other.

My baby's eyes look a different colour from each other. Is that just normal settling?

Check in ordinary daylight over a few days before worrying, because flash photography alone can make eyes look mismatched in a single picture when they are not, especially in the first year while colour is still settling. If a genuine difference is there consistently in daylight, that is heterochromia rather than ordinary colour change, and is covered fully in this site's article on two different coloured eyes.

What eye changes in the first year are not just colour settling in?

A cloudy, hazy or grey look to the clear front of the eye, or an eye that looks larger than the other or larger than it did last month, a white or pale glow that keeps recurring in flash photographs, and a very pale iris paired with real light sensitivity or wobbly eye movements. None of these is ordinary pigment developing, and each is worth naming to your child's doctor rather than watching and waiting.

Can eye colour keep changing after the first year?

For most babies the colour is essentially settled well before their first birthday, but a study following children from three months to six years found roughly 10 to 20% went on to show a further shift within that longer window. A gradual change within that range, rather than a sudden one, is still part of the same ordinary process.

Does a baby's eye colour at birth predict the final colour?

It is a reasonable early clue but not a guarantee either way. A pale, blue-grey newborn eye can darken considerably as melanin develops over the following months, while a baby already born with a deep brown iris has much less room left to change. Neither starting point rules out some further shift before the colour fully settles.

References

American Academy of Ophthalmology · Why Are My Eyes Changing Color? · www.aao.org
Ludwig et al. · What colour are newborns' eyes? Prevalence of iris colour in the Newborn Eye Screening Test (NEST) study, Acta Ophthalmologica · pmc.ncbi.nlm.nih.gov
MedlinePlus Genetics (US National Library of Medicine) · Is eye color determined by genetics? · medlineplus.gov
American Academy of Ophthalmology · What Is Albinism? · www.aao.org
Cleveland Clinic · When Do Babies' Eyes Change Color? · health.clevelandclinic.org

By Dr Chan Li Yen. General information only. It does not replace a consultation. If you are worried about your child's eyes or vision, please see an eye doctor.