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

畢竟，我們中的大多數人每天都能從鏡子裡看到他們盯著我們看。

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

雖然我們的身體可能會改變，但眼睛的顏色是永久不變的。

Until it's not!

直到它不是！

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.

有很多事情會讓你的寶寶不再那麼憂鬱，或者讓你的棕色眼睛女孩需要一個新的暱稱。

Here are just a few of them.

下面就是其中的幾個例子。

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

首先，我們先來了解一下虹膜的工作原理。

Your iris is the gatekeeper to light entering the eye.

虹膜是光線進入眼睛的 "守門員"。

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

它包含睜開和閉合瞳孔的肌肉，是以可以調節進入瞳孔的光線多少。

Irises also come in a spectrum of spectacular colors, thanks to their cellular makeup.

由於鳶尾花的細胞構成，它們還能呈現出各種絢麗的色彩。

There are two layers of the iris.

虹膜有兩層。

Within these layers, there's a whole bunch of very important stuff that all helps you see.

在這些層中，有一大堆非常重要的東西，它們都能幫助你看到。

But the bits we want to focus on are the ones that have to do with eye color, the melanocytes.

但我們要關注的是與眼睛顏色有關的部分，即黑色素細胞。

Melanocytes are found in both layers of the iris.

虹膜的兩層都有黑色素細胞。

Two-thirds of all cells in the anterior layer, which is called the iris stroma, are melanocytes.

在被稱為虹膜基質的前層，三分之二的細胞都是黑色素細胞。

So this layer is doing a lot of heavy lifting and giving your eyes their hue.

是以，這一層承擔了大量繁重的工作，為你的眼睛提供色調。

And melanocytes aren't just in your eyes.

黑色素細胞不僅僅存在於眼睛中。

They make melanin all throughout your body.

它們在全身製造黑色素。

This is the same melanin that gives your skin and hair whatever color they've got.

正是這種黑色素讓你的皮膚和頭髮呈現出各種顏色。

Melanin absorbs light, meaning it can't be reflected back to be perceived by us.

黑色素會吸收光線，這意味著光線無法反射回來，無法被我們感知。

More melanin in a spot means more light is being absorbed there, and we see it as a darker color.

黑色素越多，意味著吸收的光線越多，我們看到的顏色也就越深。

So in brown eyes, there's lots of melanin present and lots of light being absorbed.

是以，在棕色眼睛中，有大量黑色素存在，大量光線被吸收。

But lighter-colored eyes have less melanin, which means that the shorter wavelengths of light get reflected back off of collagen fibers.

但淺色眼睛的黑色素較少，這意味著較短波長的光線會被膠原纖維反射回來。

And then, when someone else looks at those melanin-lacking eyes, their eyes pick up on that reflected light, and that's how we see each other's eye color.

然後，當別人看著這雙缺乏黑色素的眼睛時，他們的眼睛會接收到反射的光線，這就是我們看到對方眼睛顏色的方式。

Melanin also comes in two forms, eumelanin, which is black or dark brown, and pheomelanin, which is light brown, yellow, or red.

黑色素也有兩種形式，一種是黑色或深棕色的 eumelanin，另一種是淺棕色、黃色或紅色的 pheomelanin。

And different combinations of eumelanin and pheomelanin will affect the color of your eyes, kind of like mixing paint colors.

黑色素和嗜黑色素的不同組合會影響眼睛的顏色，就像混合顏料的顏色一樣。

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

例如，綠色眼睛的人有更多的黃紅色嗜鉻細胞苷。

But not all eye colors are the result of melanin.

但並不是所有的眼睛顏色都是黑色素造成的。

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.

如果您患有白化病或其他幾乎沒有黑色素的疾病，視網膜上的血管反射光線，就會呈現粉紅色或淡紅色。

There's also a lot that can change in a complicated system like the eyeball.

像眼球這樣複雜的系統也會發生很多變化。

So let us talk about a few ways your eye color can change.

是以，讓我們來談談改變眼睛顏色的幾種方法。

[♪ INTRO ♪)]

[♪ INTRO ♪)]

Although babies spend about nine months developing in the womb, when they come into the world all fresh and squishy, they're not done cooking just yet.

雖然嬰兒在子宮內發育了大約九個月，但當他們來到這個世界上時，他們還沒有完成烹飪。

And it's not just growing bones and developing brains that change over the coming months and years.

在未來的歲月裡，發生變化的不僅僅是生長中的骨骼和發育中的大腦。

The eye color can change, too.

眼睛的顏色也會發生變化。

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

許多嬰兒剛出生時眼睛的顏色比成年後要淺。

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.

我們的想法是，這些 "嬰兒藍 "中的黑色素細胞要麼還沒有完成移動到位，要麼已經存在的細胞還沒有達到黑色素細胞的專業化程度。

Over the first few months of life, the iris is populated with those pigment-making cells and gets darker.

在出生後的頭幾個月裡，虹膜上的色素細胞會越來越多，顏色也會越來越深。

For the most part, the eye color will settle by around six years old.

在大多數情況下，眼睛的顏色會在六歲左右穩定下來。

But for some, it doesn't end there.

但對有些人來說，這並沒有結束。

A twin study found that 10 to 15 percent of white participants' eyes continue to darken between age six and adulthood.

一項雙胞胎研究發現，10% 到 15% 的白人参與者的眼睛在 6 歲到成年期間會繼續變黑。

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.

這種情況發生在雙胞胎身上的事實表明，眼睛顏色的年齡變化與遺傳之間存在著相當密切的聯繫，是以你的眼睛變黑甚至可能是家族遺傳。

But there's a twist.

但有一個轉折。

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.

長大成人不僅會讓眼睛變得更黑，一直到黃金年齡的衰老最終也會讓眼睛變淺。

Kind of.

有點像

Argus sinulus is a buildup of lipids that can form around the iris and give it a light blue or gray ring.

虹膜竇是一種脂質堆積物，可在虹膜周圍形成淺藍色或灰色的環。

A sort of eyeball halo, if you will.

可以說是一種眼球光環。

This usually happens in elderly people, and the new hue is usually benign.

這種情況通常發生在老年人身上，新色調通常是良性的。

But they can sometimes be a sign of another underlying condition, so it's not a bad idea to get them checked out.

但它們有時也可能是另一種潛在疾病的徵兆，所以去醫院檢查一下也未嘗不可。

There are also plenty of not-so-great eye conditions that can change your eye color.

還有很多不太好的眼疾也會改變眼睛的顏色。

There are a few that can also lead to loss of pigment and lighter eyes.

有一些疾病也會導致色素脫失和眼睛變淺。

Horner's syndrome is caused by damage or disruption to certain nerves in the head and neck.

霍納氏綜合症是由於頭部和頸部的某些神經受到損傷或破壞而引起的。

That comes with a whole bunch of neurological symptoms, but it also causes your eyes to get lighter in color.

這不僅會帶來一系列神經症狀，還會導致眼睛顏色變淺。

It's super noticeable in babies, but in adults, it can be harder to notice because it happens so slowly.

這種現象在嬰兒身上非常明顯，但在成年人身上卻很難察覺，因為它發生得很慢。

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?

你可能只有在看 20 年前的照片時才會發現這一點，然後會想，嘿，那時我的眼睛是不是黑了很多？

Likewise, Fuchs heterochromic iridocyclitis causes inflammation of structures in the front of the eye, including the iris.

同樣，福氏異色性虹膜睫狀體炎會導致眼球前部結構（包括虹膜）發炎。

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

最終，所有的發炎都會伴隨著眼睛變亮。

And are you proud of me for saying Fuchs heterochromic iridocyclitis correctly?

我說對了 "福氏異色性虹膜睫狀體炎"，你為我感到驕傲嗎？

Because I am.

因為我就是。

It's not fully understood what causes this to happen, but studies have found that people with Fuchs have fewer melanocytes and smaller melanin-producing machinery.

目前還不完全清楚發生這種情況的原因，但研究發現，Fuchs 患者的黑色素細胞數量較少，黑色素生成機制也較小。

And finally, we have pigment dispersion syndrome.

最後，我們還有色素分散綜合徵。

The name basically just means a loss of pigment, which causes your eyes to get lighter.

這個名字的基本意思是色素脫失，導致眼睛變淺。

But it's the mechanism of this particular change where things get really interesting.

但這種特殊變化的機制才是真正有趣的地方。

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.

一些研究人員認為，這種情況會導致色素脫失，因為虹膜對於眼睛來說太大了，導致眼睛向後彎曲。

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.

這種向後的彎曲會導致固定眼球晶狀體的細小線狀纖維與虹膜接觸，而這種接觸是不應該發生的。

And when that happens, those threads can literally rub the pigment off.

一旦出現這種情況，這些線頭就會把顏料磨掉。

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

它還會導致其他一些不好的事情，比如青光眼。

But fortunately, glaucoma treatments can help treat pigment dispersion syndrome, too.

但幸運的是，青光眼治療也能幫助治療色素分散綜合徵。

Now, instead of pigment gain or loss, the next one is kind of like DIY eye jewelry.

現在，下一個項目不再是色素增減，而是有點像 DIY 眼部飾品。

Kaiser-Fleischer rings are brown or grayish rings that can form a little ring around the iris.

凱澤-弗萊舍環是一種褐色或灰色的環，可在虹膜周圍形成一個小環。

They're caused by deposition of excess copper in the cornea, which lays over the top of the iris.

它們是由角膜上多餘的銅沉積造成的，角膜位於虹膜的上方。

These rings are common in patients with Wilson's disease, a genetic disorder which causes an error in copper metabolism in the body.

這種環在威爾遜氏病患者中很常見，威爾遜氏病是一種遺傳性疾病，會導致體內銅代謝出錯。

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

但它們也可能是由肝臟疾病等其他問題引起的。

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

好的一面是，只要你治療了導致它們出現的病症、

Kaiser-Fleischer rings should go away.

Kaiser-Fleischer 戒指應該消失。

Another bummer of a disease that can change eye color is cancer.

另一種會改變眼睛顏色的疾病是癌症。

Yes, iris melanomas are a thing.

是的，虹膜黑色素瘤是一種疾病。

They are not super common, but they do happen.

這種情況並不常見，但確實存在。

Just like a skin melanoma, iris melanoma is a cancer starting in the melanocytes.

與皮膚黑色素瘤一樣，虹膜黑色素瘤也是從黑色素細胞開始發生的癌症。

And just as on the skin, this can present on the iris as dark brownish spots.

就像皮膚一樣，虹膜上也會出現深褐色斑點。

They can also cause you to start seeing more floaters, and can change the shape of your pupil.

它們還可能會讓你看到更多的漂浮物，並改變你的瞳孔形狀。

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.

大多數虹膜黑色素瘤並不明顯，但如果您的虹膜上出現了新的黑斑，可能就需要預約醫生了。

And not only can a cancer cause your eye color to change, treating cancers can cause it too.

不僅癌症會導致眼睛變色，治療癌症也會導致眼睛變色。

There's a rare type of eye cancer found in young children called retinoblastoma that is super aggressive.

有一種在幼兒中發現的罕見眼癌叫做視網膜母細胞瘤，它具有超強的侵襲性。

But there is 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.

但目前有一種治療視網膜母細胞瘤的新方法，即在玻璃體中注射化療藥物，玻璃體是位於患眼晶狀體和視網膜之間的膠凍狀物質。

This sounds terrible, but, like, we're getting a cancer!

這聽起來很可怕，但是，就像我們得了癌症一樣！

And while that treatment seems to work pretty well, there are a couple of 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.

雖然這種治療方法看起來效果不錯，但也有一些案例研究表明，這種治療方法也會導致那隻眼睛的顏色變淺，從而使這些孩子患上永久性異色症，這也是一個值得講述的故事。

We have more cool science to share, but first, let me tell you about another way to learn cool science.

我們還有更多很酷的科學知識要分享，但首先，讓我告訴你另一種學習很酷科學知識的方法。

Brilliant.

真聰明

With Brilliant, you don't even need to limit yourself to science.

有了 Brilliant，你甚至不需要侷限於科學。

You can choose from thousands of lessons in computer science and math as well, all on one interactive learning platform.

您還可以從數以千計的計算機科學和數學課程中進行選擇，所有課程都在一個互動學習平臺上進行。

You can learn artificial intelligence with the help of professionals at Microsoft and

您可以在微軟專業人員的幫助下學習人工智能，還可以

Google, and you can harness some of the most advanced tools of our time, like large language models.

在谷歌，你可以利用我們這個時代最先進的工具，比如大型語言模型。

With Brilliant, you can train models on real data and generate all kinds of products, like a poem or a cover letter.

利用 Brilliant，您可以在真實數據上訓練模型，生成各種產品，如一首詩或一封求職信。

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.

通過比較泰勒-斯威夫特（Taylor Swift）模型和烹飪書模型的結果，您可以瞭解模型所訓練的數據是如何改變產品的。

While you're playing around with those variables, you'll build an understanding of large language models from the ground up.

在玩弄這些變量的同時，您將從根本上了解大型語言模型。

And since you learn this stuff through hands-on problem solving, you'll be more likely to actually remember it.

而且，因為你是通過動手解決問題來學習這些知識的，所以你會更容易記住它們。

To get started, head over to Brilliant.org slash SciShow, or the link in the description down below.

要開始學習，請訪問 Brilliant.org slash SciShow 或下面描述中的鏈接。

That link will also give you 20% off an annual Premium Brilliant subscription, and you'll get your first 30 days for free.

通過該鏈接，您還可以以 20% 的折扣訂購年度 Premium Brilliant，而且前 30 天是免費的。

And thank you to Brilliant for supporting this SciShow video.

感謝 Brilliant 對 SciShow 視頻的支持。

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.

現在，我們已經討論了很多能改變眼睛顏色的怪病，但有些藥物也能改變眼睛顏色。

One of the most common is a medication group called prostaglandins, which are used to treat glaucoma.

其中最常見的是一種名為前列腺素的藥物，這種藥物用於治療青光眼。

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.

青光眼是一組疾病的總稱，這些疾病會導致眼壓升高，久而久之會損傷視神經。

And prostaglandins are great at lowering that pressure, so they are great for treating glaucoma.

而前列腺素能很好地降低壓力，是以是治療青光眼的好幫手。

And they are also known for a weird side effect — darkening people's irises.

它們還有一個奇怪的副作用--使人的虹膜變黑。

One study found that the glaucoma medication latanoprost caused between 5 to 23% of patients' eyes to get darker after 12 months of treatment.

一項研究發現，青光眼藥物拉坦前列素在治療 12 個月後會導致 5%到 23%的患者眼睛變黑。

It's probably still a good idea to take these medications either way.

無論如何，服用這些藥物可能都是個好主意。

Just don't be surprised if you notice a new eye shade in your reflection afterwards.

如果事後你發現自己的反光鏡中出現了新的眼影，千萬不要驚訝。

We've talked about dark flecks and white rings on the iris, but how about patchwork eye color?

我們已經討論過虹膜上的黑斑和白環，那麼拼接眼色又如何呢？

Vitiligo is an autoimmune disorder where your immune system turns on your melanocytes and destroys them.

白癜風是一種自身免疫性疾病，免疫系統會攻擊並破壞黑色素細胞。

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.

當皮膚出現這種情況時，通常會更加明顯，因為它會導致大片皮膚變得比原來淺得多。

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.

但眼睛中的黑色素細胞也可能出現這種情況，這可能表現為虹膜上的斑狀藍斑或更廣泛的色素脫失。

This specific presentation of vitiligo is often associated with specific eye-related syndromes like Vogt-Koyanagi-Hirata syndrome and Alatangrini's syndrome, but can also happen in the more general full-body vitiligo.

這種特殊表現的白癜風通常與特定的眼部相關綜合徵有關，如 Vogt-Koyanagi-Hirata 綜合徵和 Alatangrini 綜合徵，但也可能發生在更普遍的全身性白癜風中。

Now, this is probably the most temporary eye color-swapping method on the list, but your eye color can look really different depending on your emotional state.

現在，這可能是列表中最臨時的眼色交換方法了，但你的眼色會隨著你的情緒狀態而變化。

Novelists might be taking some artistic liberty when they describe eyes becoming dark and stormy and anger, but there really is something there.

小說家在描寫眼睛變得陰沉、暴怒時，可能會有一些藝術上的隨意性，但確實有一些東西存在。

Not all eye color changes come down to the iris.

並非所有眼睛顏色的變化都與虹膜有關。

The size of the pupil plays a role, too.

瞳孔的大小也有影響。

Your pupil dilates differently when you are processing different emotions.

當你在處理不同情緒時，瞳孔會以不同的方式放大。

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.

一項研究發現，與快樂或中性的感覺相比，恐懼會導致瞳孔更大幅度地放大，由於虹膜的可見度降低，眼睛會暫時呈現出不同的顏色。

And of course, this isn't really an eye color change, but it is the illusion of one.

當然，這並不是真正的眼球變色，只是一種假象。

Another illusory eye color change can come from trauma to the brain or eye.

另一種虛幻的眼球顏色變化可能來自於大腦或眼睛的外傷。

A nasty knock on the head can cause your pupil to get permanently stuck at full dilation.

頭部受到嚴重撞擊會導致瞳孔長期處於完全放大狀態。

And like we mentioned before, greater pupil size equals less visible iris and a whole different-looking eye color.

就像我們之前提到的，瞳孔越大，虹膜就越不明顯，眼睛的顏色就會完全不同。

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

這種情況可能發生在雙眼，但通常只發生在單眼。

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.

如果這種情況發生在你身上，那你就有福了，因為永久性瞳孔破裂也是造成大衛-鮑伊那雙著名的錯位眼的原因。

Whether it also makes you a rock legend?

它是否也能讓你成為搖滾傳奇？

Less clear?

不太清楚？

Everything we've talked about so far that can change your eye color comes down mostly to just, like, a roll of the dice.

到目前為止，我們討論過的所有能改變眼睛顏色的方法，大部分都是擲骰子。

But what if you could choose your own adventure, and actually select your eye color?

但是，如果你可以選擇自己的冒險，並真正選擇自己的眼睛顏色呢？

It sounds like science fiction, but for some, this has become a reality.

這聽起來像科幻小說，但對某些人來說，這已成為現實。

Congenital aniridia is a rare genetic eye disorder where you are born without a part of or all of your iris.

先天性虹膜缺失症是一種罕見的遺傳性眼部疾病，患者出生時就沒有部分或全部虹膜。

As with trauma to the eye, this means that your pupil is larger and your eyes look darker.

與眼外傷一樣，這意味著瞳孔變大，眼睛看起來更黑。

Not the pupil control.

不是瞳孔控制。

This, of course, leaves people with a sensitivity to light, but it can also lead to vision loss.

這當然會讓人對光線敏感，但也可能導致視力下降。

But there is a procedure that can help correct this — an iris implant.

但有一種手術可以幫助糾正這種情況，那就是虹膜植入術。

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.

它們尚未獲得美國食品和藥物管理局的準許，但在美國，醫生可以基於同情的理由獲得使用豁免，在其他一些國家也可以使用。

And the caution to approve them for wider-scale use might be warranted.

在準許更廣泛地使用它們時，可能需要謹慎行事。

Because although iris implants might improve vision and reduce glare in individuals with aniridia, they might also cause some nasty complications, like glaucoma.

因為雖然虹膜植入術可以改善無虹膜症患者的視力並減少眩光，但也可能會引起一些令人討厭的併發症，如青光眼。

These prostheses are still pretty new, so it's up to each individual and their doctor to weigh the risks and benefits.

這些假體還很新，是以每個人和他們的醫生都要權衡其風險和益處。

So if you do have a condition where having a new iris could really help, technically, you could go for any color you want.

是以，如果你有某種疾病，換一個新的虹膜確實會有幫助，從技術上講，你可以選擇任何你想要的顏色。

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

也許可以在上面畫一些條紋，讓它變得更時髦。

So now you know!

現在你知道了吧！

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

改變眼睛顏色有很多可能。

And while it might be jarring to see such a change, no matter what color they are, we think that beauty is in the eyes of the beholder.

雖然看到這樣的變化可能會讓人感到刺眼，但無論它們是什麼顏色，我們都認為，美就在觀賞者的眼中。

[♪ OUTRO ♪, thanks for watching!]

[OUTRO，感謝您的收看！]