11 Things That Can Change Your Eye Color

Summary

This script delves into the fascinating factors influencing eye color changes, from the melanocytes' role in determining hues to the impact of age, genetics, and various health conditions. It explores how babies' eye colors can evolve and how conditions like Horner's syndrome or Fuchs heterochromic iridocyclitis can alter iris hues. The video also touches on rare occurrences like iris melanomas and the potential for eye color to be influenced by emotional states or even permanently altered by trauma. Innovative solutions like iris implants for congenital aniridia are introduced, highlighting the complex interplay of biology, genetics, and modern medicine in our perception of eye color.

Takeaways

• 👀 Eye color can change over time due to various factors.
• 🧬 Melanocytes in the iris determine eye color by producing melanin.
• 👶 Many babies are born with lighter eye colors that darken as they age.
• 👵 Eyes can lighten in old age due to conditions like arcus senilis.
• 🩺 Certain medical conditions, like Horner’s syndrome and Fuchs heterochromic iridocyclitis, can cause eyes to lighten.
• 🧬 Albinism results in little to no melanin, leading to pink or reddish eyes.
• 🧬 Green eyes have more pheomelanin, which is yellow-red.
• 💊 Medications, like prostaglandins for glaucoma, can darken eye color.
• 🦠 Conditions such as vitiligo can cause patchy loss of pigment in the eyes.
• 🔬 Iris implants are a potential solution for congenital aniridia, allowing for customized eye colors.

Q & A

What is the role of the iris in the eye?

The iris acts as the gatekeeper to light entering the eye, containing the muscle to open and close the pupil, thus regulating the amount of light that enters.

How does the iris achieve its various colors?

The iris's colors are due to its cellular makeup, particularly the melanocytes found in both layers of the iris, which produce melanin that absorbs light and gives the eyes their hue.

What is melanin and how does it affect eye color?

Melanin is a pigment produced by melanocytes throughout the body, including in the iris. It absorbs light and does not reflect it back, making areas with more melanin appear darker.

How do the amounts of eumelanin and pheomelanin influence eye color?

Different combinations of eumelanin (black or dark brown) and pheomelanin (light brown, yellow, or red) affect the color of the eyes, similar to mixing paint colors.

Why might a person's eye color change after birth?

Eye color can change after birth because melanocytes in the iris may not be fully in place or specialized yet, and over the first few months of life, the iris becomes populated with these pigment-making cells, causing the eyes to darken.

At what age does eye color typically stabilize?

For most people, eye color stabilizes by around six years old, although a twin study found that 10-15% of white participants' eyes continued to darken between age 6 and adulthood.

What is Arcus senilis and how does it affect eye color?

Arcus senilis is a buildup of lipids around the iris that can give it a light blue or gray ring, typically occurring in elderly people and usually being benign.

How can Horner’s syndrome affect a person's eye color?

Horner’s syndrome, caused by damage or disruption to certain nerves in the head and neck, can cause the eyes to get lighter in color due to a reduction in melanin.

What is Fuchs heterochromic iridocyclitis and how does it impact eye color?

Fuchs heterochromic iridocyclitis is an inflammation of structures in the front of the eye, including the iris, which can eventually lead to a lightening of the eyes due to fewer melanocytes and smaller melanin-producing machinery.

What is pigment dispersion syndrome and how does it cause eye color to change?

Pigment dispersion syndrome involves a loss of pigment, causing the eyes to get lighter. It is thought to occur when the iris is too big for the eye, causing it to bow backward and allowing fibers that hold the lens in place to rub the pigment off the iris.

Can eye color change be a side effect of certain medications?

Yes, certain medications, such as prostaglandins used to treat glaucoma, can cause the iris to darken as a side effect.

How can vitiligo affect the appearance of eye color?

Vitiligo is an autoimmune disorder that can destroy melanocytes in the eyes, resulting in patchy blue spots in the iris or more widespread loss of pigment, which can change the appearance of eye color.

What is one way that emotional state can create the illusion of a change in eye color?

The pupil can dilate differently when processing different emotions. Fear, for example, can cause the pupil to dilate more drastically, temporarily making the eyes look a different color as less of the iris is visible.

What is an iris implant and how can it be used to change eye color?

An iris implant is a medical procedure that can help correct congenital aniridia, a condition where a person is born without a part or all of their iris. While not yet FDA approved for widespread use, these implants can technically allow individuals to select any color for their new iris.

Outlines

00:00

👁️ How the Iris Determines Eye Color

Our understanding of eye color starts with the iris, the muscle regulating light entry by adjusting the pupil size. The iris's cellular structure, particularly melanocytes, plays a crucial role in eye color. Melanocytes produce melanin, the pigment responsible for color in the skin, hair, and eyes. More melanin results in darker colors, while less melanin leads to lighter hues. Different types of melanin, eumelanin and pheomelanin, combine to create various eye colors. Conditions like albinism, where melanin is scarce, can cause unique eye colors like pink or reddish hues. Understanding these mechanisms helps us grasp why eye color can change under certain conditions.

05:01

👶 Why Babies' Eye Color Changes Over Time

Many babies are born with lighter eye colors that darken over time. This is due to melanocytes not being fully developed or in place at birth. Eye color generally settles by age six, though it can continue to change into adulthood. Twin studies suggest a genetic link to these changes. Interestingly, aging can cause eyes to lighten, such as with arcus senilis, a lipid build-up around the iris creating a light ring. This usually occurs in the elderly and is typically benign but may indicate other health issues. Other conditions like Horner’s syndrome and Fuchs heterochromic iridocyclitis can also lighten eye color through neurological damage or inflammation.

10:03

👁️‍🗨️ Eye Conditions and Color Changes

Conditions like pigment dispersion syndrome, where the iris rubs against eye structures, can cause pigment loss and lighter eyes. Kayser-Fleischer rings, due to copper deposits from conditions like Wilson’s disease, form brown or gray rings on the iris but can be treated by addressing the underlying disease. Iris melanomas, a type of cancer, can also alter eye color and present as dark spots, requiring medical attention. Treatments for cancers like retinoblastoma can also change eye color, sometimes resulting in heterochromia. These examples show how various health conditions and treatments can affect eye color.

💊 Medications and Eye Color Alterations

Medications, particularly prostaglandins used for glaucoma treatment, can darken eyes over time. Glaucoma increases eye pressure, damaging the optic nerve, and prostaglandins help reduce this pressure. However, they can also cause the iris to darken, with a significant percentage of patients experiencing this change. Vitiligo, an autoimmune disorder targeting melanocytes, can create patchy color changes in the iris, often associated with specific syndromes. Emotional states and pupil dilation can also temporarily alter the perceived eye color, with emotions like fear causing more significant dilation and apparent color shifts.

🧠 Trauma and Artificial Eye Color Changes

Trauma to the brain or eye can cause permanent pupil dilation, changing the visible eye color. This can happen in one or both eyes, as seen with David Bowie’s mismatched eyes. While most eye color changes are natural or due to conditions, some individuals with congenital aniridia, a lack of iris, might opt for iris implants. These implants, though not widely approved, can reduce light sensitivity and improve vision, but they carry risks like glaucoma. Advances in this area suggest the potential for choosing eye colors, highlighting ongoing developments in eye health and aesthetics.

Keywords

💡Eye Color

Eye color is determined by the amount and type of pigments in the iris, the colored part of the eye. In the video, it is the central theme, as it discusses how various factors can alter eye color throughout a person's life. For instance, the script mentions that babies can be born with lighter eyes that darken over time due to the maturation of melanocytes.

💡Iris

The iris is the part of the eye that controls the amount of light entering by adjusting the size of the pupil. It contains melanocytes which are responsible for eye color. The script explains that the iris has two layers and that the melanocytes in these layers give the eyes their hue, with the anterior layer, known as the iris stroma, being particularly important.

💡Melanocytes

Melanocytes are the cells found in the iris that produce melanin, the pigment responsible for determining skin, hair, and eye color. The video script emphasizes their role in eye color by explaining that a higher concentration of melanocytes results in darker eyes, while fewer melanocytes lead to lighter eyes.

💡Melanin

Melanin is a pigment that absorbs light and gives color to various parts of the body, including the eyes. The script describes how the presence of melanin in the iris affects eye color, with more melanin leading to darker eyes and less melanin allowing light to be reflected, resulting in lighter eye colors.

💡Eumelanin and Pheomelanin

These are two types of melanin discussed in the script. Eumelanin is responsible for black or dark brown coloration, while pheomelanin gives a light brown, yellow, or red hue. The combination of these melanins affects the final color of the eyes, similar to mixing paint colors.

💡Albinism

Albinism is a genetic condition characterized by a lack of melanin production. The script explains that in individuals with albinism or similar conditions, the lack of melanin results in the blood vessels in the retina reflecting light, giving the eyes a pink or reddish hue.

💡Aging and Eye Color

The script discusses how aging can affect eye color, specifically mentioning 'Arcus senilis,' a condition where lipids accumulate around the iris, creating a light blue or gray ring. This change in eye color is typically benign but can also indicate an underlying health issue.

💡Horner’s Syndrome

Horner’s Syndrome is a condition caused by damage or disruption to certain nerves in the head and neck. The script notes that it can cause the eyes to become lighter in color, a change that is particularly noticeable in babies but can be more subtle in adults.

💡Pigment Dispersion Syndrome

Pigment Dispersion Syndrome is a condition where pigment from the iris is lost, resulting in lighter eyes. The script provides a unique explanation for this phenomenon, suggesting that an oversized iris may bow backward, causing fibers that hold the lens in place to rub off the pigment.

💡Kayser-Fleischer Rings

Kayser-Fleischer Rings are described in the script as brown or grayish rings that form around the iris due to the deposition of excess copper in the cornea. They are commonly associated with Wilson’s disease, a genetic disorder affecting copper metabolism, but can also be caused by liver disease.

💡Cancer and Eye Color

The script mentions that iris melanomas, a type of cancer that starts in the melanocytes, can change eye color by presenting as dark brownish spots on the iris. It also discusses how certain treatments for eye cancer, such as chemotherapy for retinoblastoma, can result in a lighter eye color.

💡Prostaglandins

Prostaglandins are a group of medications used to treat glaucoma by lowering eye pressure. The script highlights a peculiar side effect of these drugs: they can cause the iris color to darken, as evidenced by a study where latanoprost treatment resulted in eye color darkening in a percentage of patients.

💡Vitiligo

Vitiligo is an autoimmune disorder where the immune system attacks melanocytes, causing a loss of pigment. The script explains that vitiligo can affect the eyes, resulting in patchy blue spots in the iris or a more widespread loss of pigment, which can be associated with specific eye-related syndromes.

💡Emotional State and Eye Color

The script touches on the idea that emotional states can affect the appearance of eye color. It mentions a study that found fear can cause the pupil to dilate more than happiness or neutrality, which would make the eyes appear a different color due to less iris being visible.

💡Trauma and Eye Color

Trauma to the eye or brain can result in a permanently dilated pupil, as mentioned in the script. This condition can alter the appearance of eye color because a larger pupil reveals less iris, creating the illusion of a color change.

💡Congenital Aniridia

Congenital Aniridia is a rare genetic disorder where a person is born without part or all of their iris. The script describes how this condition leads to a larger pupil and darker appearing eyes, and mentions the possibility of iris implants as a corrective procedure, although they are not yet widely approved.

Highlights

Eye color is generally permanent but can change due to various factors.

The iris contains melanocytes which are responsible for eye color through melanin production.

Melanin absorbs light, affecting the perceived color of the eyes.

Different combinations of eumelanin and pheomelanin create a range of eye colors.

Conditions like albinism can cause a pink or reddish hue due to blood vessel reflection.

Babies' eye color can change as melanocytes finish developing and populating the iris.

Eye color can continue to darken between age 6 and adulthood due to genetics.

Aging can cause Arcus senilis, a light blue or gray ring around the iris due to lipid buildup.

Certain medical conditions like Horner’s syndrome can cause eye color to become lighter.

Inflammation from conditions like Fuchs heterochromic iridocyclitis can lead to lighter eyes.

Pigment dispersion syndrome can cause lighter eyes due to the iris rubbing against lens fibers.

Kayser-Fleischer rings, caused by copper deposition, can change eye appearance in Wilson’s disease.

Iris melanomas, though rare, can appear as dark spots and change eye color.

Cancer treatments can sometimes lead to changes in eye color.

Medications like prostaglandins used for glaucoma can have the side effect of darkening the iris.

Vitiligo can cause patchy loss of pigment in the iris, affecting eye color.

Emotional states can temporarily alter the appearance of eye color due to pupil dilation.

Trauma can result in a permanently dilated pupil, changing the visible iris size and eye color.

Congenital aniridia, a disorder without an iris, can be corrected with iris implants, allowing for a choice of eye color.

Transcripts

You probably think you know the  color of your eyes pretty well.

After all, most of us see them staring  back at us in the mirror every day.

And while our bodies may  change, eye color is permanent.

Until it’s not.

There are a shocking number of things that  can make your baby blues not so blue anymore,

or can make your brown-eyed  girl need a new nickname.

Here are just a few of them.

First, let’s start by breaking  down how the iris works.

Your iris is the gatekeeper  to light entering the eye.

It contains the muscle to open and close the pupil  so it regulates how much light gets in there.

Irises also come in a  spectrum of spectacular colors

thanks to their cellular makeup.

There are two layers of the iris.

Within these layers,

there’s a whole bunch of very important stuff

that all helps you see.

But the bits we want to focus on

are the ones that have to do with eye color,

the melanocytes.

Melanocytes are found in both layers of the iris.

Two thirds of all cells in the anterior layer,

which is called the iris stroma, are melanocytes.

So this layer is doing a lot of heavy lifting

in giving your eyes their hue.

And melanocytes aren’t just in your eyes.

They make melanin all throughout your body.

This is the same melanin that gives your skin

and hair whatever color they’ve got.

Melanin absorbs light,

meaning it can’t be reflected back

to be perceived by us.

More melanin in a spot

means more light is being absorbed there,

and we see it as a darker color.

So in brown eyes there’s lots of melanin present

and lots of light being absorbed.

But lighter-colored eyes have less melanin,

which means that the shorter wavelengths of light

get reflected back off of collagen fibers.

And then when someone else looks  at those melanin-lacking eyes,

their eyes pick up on that reflected light,

and that is how we see each other’s eye color.

Melanin also comes in two forms, eumelanin,

which is black or dark brown,

and pheomelanin,

which is light brown, yellow, or red.

And different combinations  of eumelanin and pheomelanin

will affect the color of your eyes,

kind of like mixing paint colors

For example,

people with green eyes have more  of that yellow-red pheomelanin.

But not all eye colors are the result of melanin.

If you’ve got albinism or another condition

where you have little to no melanin,

it’s the blood vessels in the  retina reflecting back light

that give a pink or reddish hue.

There’s also a lot that can change

in a complicated system like the eyeball,

so let us talk about a few  ways your eye color can change!

[ INTRO MUSIC ]

Although babies spend about 9  months developing in the womb,

when they come into the  world all fresh and squishy,

they are not done cooking just yet.

And it’s not just growing  bones and developing brains

that change over the coming months and years.

The eye color can change, too.

Many babies have lighter eyes at  birth than they will as adults.

The idea is that melanocytes in those baby blues

are either not finished moving into place

or the cells that are there

haven’t gotten around to  specializing as melanocytes yet.

Over the first few months of life,

the iris is populated with  those pigment making cells

and gets darker.

For the most part, the eye color

will settle by around six years old.

But for some it doesn’t end there.

A twin study found that 10-15%  of white participants’ eyes

continued to darken between age 6 and adulthood.

The fact that this happens in twins

shows a pretty strong link

between age-changing eye color and genetics,

so your darkening eyes might  even run in the family.

But there’s a twist!

Not only can growing to adulthood  cause your eyes to get darker,

aging all the way to your golden years

can eventually make your eyes lighter.

Kind of.

Arcus senilis is a build up of lipids

that can form around the iris

and give it a light blue or gray ring.

A sort of eyeball halo if you will.

This usually happen in elderly people

and the new hue is usually benign.

But they can sometimes be a sign  of another underlying condition.

So it’s not a bad idea to get them checked out.

There are also plenty of  not-so-great eye conditions

that can change your eye color.

There are a few that can also lead

to loss of pigment and lighter eyes.

Horner’s syndrome is caused  by damage or disruption

to certain nerves in the head and neck.

That comes with a whole bunch  of neurological symptoms,

but it also causes your eyes  to get lighter in color.

It’s super noticeable in babies, but in adults,

it can be harder to notice  because it happens so slowly.

You might only spot it

when you look at a photo  from 20 years ago and think,

“hey, were my eyes like, way darker back then?”

Likewise, Fuchs heterochromic iridocyclitis

causes inflammation of structures  in the front of the eye,

including the iris.

And eventually, all that inflammation  comes with a lightening of the eyes.

And are you proud of me for saying,

“Fuchs heterochromic iridocyclitis” correctly?

Because I am.  

It’s not fully understood  what causes this to happen,

but studies have found

that people with Fuch’s have fewer melanocytes

and smaller melanin producing machinery.

And finally, we have pigment dispersion syndrome.

The name basically just means a loss of pigment,

which causes your eyes to get lighter.

But it's the mechanism of this particular change

where things get really interesting.

Some researchers have proposed

that pigment loss happens with this condition

because the iris is just too big for the eye,

which causes it to bow backwards.

This backward bowing

causes the tiny thread-like fibers

that hold the eye's lens in place

to come into contact with the iris,

which they are not supposed to do.

And when that happens,

those threads can literally rub the pigment off.

It can also cause some other  not-great things like glaucoma.

But fortunately, glaucoma treatments

can help treat pigment dispersion syndrome, too.

Now instead of pigment gain or loss,

the next one is kinda like DIY eye jewelry.

Kayser-Fleischer rings are brown or grayish rings

that can form a little ring around the iris.

They’re caused by deposition  of excess copper in the cornea,

which lays over the top of the iris.

These rings are common in  patients with Wilson’s disease,

a genetic disorder which causes an error

in copper metabolism in the body,

but they can also be caused by  other problems like liver disease.

On the plus side,

as long as you treat the condition  that caused them to appear,

Keyser-Fleischer rings should go away.

Another bummer of a disease

that can change eye color is cancer.

Yes, iris melanomas are a thing.

They’re not super common,

but they do happen.

Just like a skin melanoma, iris melanoma

is a cancer starting in the melanocytes.

And just as on the skin,

this can present on the  iris as dark brownish spots.

They can also cause you to  start seeing more floaters,

and can change the shape of your pupil.

Most iris melanomas will not be visible,

but if new dark spots appear on your iris,

it’s probably time to book an  appointment with your doctor.

And not only can a cancer  cause your eye color to change,

treating cancers can cause it too.

There’s a rare type of eye  cancer found in young children

called retinoblastoma that is super aggressive.

But there’s a new treatment for retinoblastoma

which involves injecting chemotherapy drugs

into the vitreous humor,

which is the jelly-like substance

between your lens and retina,

of the affected eye.

This sounds terrible, but like…

we're getting the cancer.

And while that treatment  seems to work pretty well,

there are a couple case studies

that suggest the treatment also resulted

in that eye getting lighter,

giving those kids permanent heterochromia

and a hell of a story to tell.

We’ve got more cool science to share.

But first, let me tell you about another way

to learn cool science: Brilliant.

With Brilliant,

you don’t even need to limit yourself to science.

You can choose from thousands of lessons

in computer science and math too!

All on one interactive learning platform.

You can learn artificial intelligence

with the help of professionals  at Microsoft and Google.

And you can harness some of the  most advanced tools of our time,

like large language models.

With Brilliant,

you can train models on real data  and generate all kinds of products,

like a poem or cover letter.

And you can learn how the data your model trains

on changes the product by comparing what comes

from a model trained on Taylor Swift

versus one trained on a cookbook.

While you’re playing with those variables,

you’ll build an understanding  of large language models

from the ground up.

And since you learn this stuff  through hands-on problem solving,

you’re more likely to actually remember it.

To get started, head to Brilliant.org/SciShow

or the link in the description down below.

That link also gives you 20% off an  annual premium Brilliant subscription.

And you’ll get your first 30 days for free!

And thank you to Brilliant for  supporting this SciShow video!

Now we’ve talked about a lot of weird diseases

that can change your eye color,

but there are some medications  that can do this too.

One of the most common is a medication group

called prostaglandins,

which are used to treat glaucoma.

Glaucoma is just a blanket  term for a group of conditions

that cause increased pressure in your eye,

and over time, damage to the optic nerve.

And prostaglandins are great  at lowering that pressure,

so they are great for treating glaucoma.

And they are also known for a weird side effect –

darkening people’s irises.

One study found that the  glaucoma medication latanoprost

caused between 5 to 23% of patients’ eyes

to get darker after 12 months of treatment.

It’s probably still a good idea

to take these medications either way.

Just don’t be surprised if  you notice a new eye shade

in your reflection afterwards.

We’ve talked about dark flecks  and white rings on the iris,

but how about patchwork eye color?

Vitiligo is an autoimmune disorder

where your immune system

turns on your melanocytes and destroys them.

It’s usually more apparent when  it’s happening in the skin,

since it causes large patches  of skin to become much lighter

than they were before.

But it can happen to melanocytes in your eyes too,

which can look like patchy blue spots in the iris,

or more widespread loss of pigment.

This specific presentation of vitiligo

is often associated with  specific eye related syndromes

like Vogt-Koyanagi-Harada syndrome

and Alezzandrini's syndrome

but can also happen in the more  general, full body vitiligo.

And this is probably

the most temporary eye color  swapping method on our list –

but your eye color can look really different

depending on your emotional state.

Novelists might be taking some artistic liberty

when they describe eyes becoming  “dark and stormy” in anger

but there really is something there.

Not all eye color changes come down to the iris.

The size of the pupil plays a role too.

Your pupil dilates differently

when you are processing different emotions.

One study found that fear

can cause the pupil to dilate more drastically

than feelings of happiness or neutrality,

which would temporarily make your eyes

look a different color as  less of your iris is visible.

And of course this isn't  really an eye color change,

but it is the illusion of one.

Another illusory eye color change

can come from trauma to the brain or eye.

A nasty knock on the head can cause your pupil

to get permanently stuck at full dilation.

And, like we mentioned before,

greater pupil size equals less visible iris

and a whole different looking eye color.

This can happen in both eyes  but usually it’s just one.

And if this ever happens to you,

you're in good company,

since a permanently blown pupil

was also the cause of David Bowie’s

famous mismatched eyes.

Whether it also makes you a rock legend…

less clear.

Everything we’ve talked about so far

that can change your eye color

comes down mostly to a roll of the dice.

But what if you could choose your own adventure

and actually select your eye color.

It sounds like science fiction but for some,

this has become a reality.

Congenital aniridia is a rare genetic eye disorder

where you are born without a  part of or all of your iris.

As with trauma to the eye,

this means that your pupil is  larger and your eyes look darker.

Without the pupil control,

this of course leaves people  with sensitivity to light

and even lead to vision loss.

But there’s a procedure  that can help correct this -

an iris implant!

They are not FDA approved yet,

but doctors can get exemptions

to use them on compassionate grounds in the US,

and they are available in some other countries .

And the caution to approve  them for wider scale use

might be warranted.

Because although iris implants

might improve vision and  reduce glare in individuals

with aniridia,

they might also cause some nasty complications

like glaucoma.

These prostheses are still pretty new,

so it’s up to each individual and their doctor

to weigh the risks and benefits.

So if you do have a condition

where having a new iris could  really help, technically,

you could go for any color you want.

Maybe throw some stripes on  there and get funky with it.

So now you know!

There’s a lot that can happen  to change your eye color.

And while it may be jarring to see such a change,

no matter what color they are,

we think that beauty is in  the eyes of the beholder.

[outro]