Secretly Incredibly Fascinating - Heterochromia

Episode Date: May 12, 2025

Alex Schmidt and Katie Goldin explore why heterochromia is secretly incredibly fascinating.Visit http://sifpod.fun/ for research sources and for this week's bonus episode.Come hang out with us on the SIF Discord: https://discord.gg/wbR96nsGg5

Heterochromia, known for being eye color, famous for being two different eye colors. Nobody thinks much about it, so let's have some fun. Let's find out why heterochromia is secretly incredibly fascinating. Hey there, folks. Welcome to a whole new podcast episode, a podcast all about why being alive is more interesting than people think it is. My name is Alex Schmidt and I'm not alone. I'm joined by my co-host Katie golden Katie Yes, what is your relationship to or opinion of?

Heterochromia so I don't know a huge amount about it. I I don't have it me neither. I know means Differently colored eyes. I think it can both mean one eye is one color, the other eye is another color, or you have an eye that has two colors, like the iris has two colors simultaneously. Yeah, that's right. And the other thing I know about it is,

I believe that in, it's not a hard and fast rule, but in pure white cats, ones that have blue eyes will often have deafness. And in white cats that have blue eyes and one of their eyes is a different color, the deafness is usually next to the blue eye in that ear. So it's very, there's weird genetics that are involved in eye color with, I don't think the same thing happens with people, human people. I don't believe there's any correlation between eye color and deafness, but it's very interesting.

Very interesting genetic shenanigans. Yeah. And we'll talk about dogs a bit, especially at the end of the show. Yeah. Either way, it seems like dogs, cats, horses, and some other mammals that we domesticate a lot, we have noticed little genetic bottlenecks of heterochromia that are just different from how it is in humans. Like that cat thing.

Yeah. But like there's something people call an odd-eyed cat, where it's a cat with heterochromia and then maybe also some of that. Well, I think their eyes are beautiful. Nothing odd about them. Yeah, take that Namers of beautiful. Nothing odd about them. Yeah, take that Namers. Yeah, take that. People who name stuff, you ding-dongs. Also, apparently, there's some scientific language around the word heterochromia applying to changes

in skin or hair pigment, but today we're talking about the eyes, the famous heterochromia. And thank you to you, Agent on the Discord, for suggesting this topic. I also knew almost nothing about it and now know a lot. It feels great. Wonderful. It's very interesting, it turns out. Yeah.

But I'd heard of it. Like it is a thing in the world, it's SIF. It's one of those things that seems a little bit magical, right, because we're so used to eyes being the same color that when you see a person or a cat or a dog or something that has these two different eye colors, it I think gives that glimpse into how interesting genes can be. Because we're used to a lot of interesting ways that genetics can surface. Like if you look at your fingers, you can find some people will have little baby fuzz on certain parts of their finger versus other people. But that's not as striking as seeing two different colored eyes.

Right, right. Yeah, it speaks to the importance of eyes and everything we feel about other beings in the world. Yes. About all the rest of the body. It's like, whatever. Okay. Yeah. in the world. Yes. About all the rest of the body. It's like, yeah, whatever. Okay. Yeah. Yeah. It's not the window to anything.

The hair finger. Hair fingers are window into the soul. And on every episode, we lead with a quick set of fascinating numbers and statistics. This week, that's in a segment called... Here I am once again. I'm reading the statistics. Can't deny it. Can't pretend that numbers are not fun. Counting up all the stats.

Cause I'm tabulating these tears I cry. Bow bow. 3.14 is pi. Oh no, don't cry about that Alex. It's gonna be a long one. These tears I cry, bow bow. 3.14 is pi. Oh no, don't cry about that, Alex. It's gonna be all right. I can't handle it.

Circles, circle map, ah! Alex just wants it to be a nice even number, not a endless decimal. And that name was submitted by Nina D. Thank you, Nina. We have a new name for this every week. Please make a Missillian Wacken pass possible. Submit through Discord or to sifpot at gmail.com. And the first number this week is genetic.

It's at least 61 genes. 61! And that's how many genes might be involved in human eye color in general, and not specifically heterochromia. Yeah, because it's not just... The way we learn it is there is blue eyes and there is brown eyes. And the brown eyes is at capital B, and the blue eyes is at lowercase b. And the blue eyes are recessive and the brown eyes are dominant.

And so everyone learns this and then any variation in that is not necessarily taught in elementary school, but it's not that simple. Yeah, I was so surprised because yeah, there's apparently pretty recent common wisdom that eyes are what we call Mendelian, which is what Katie described. It's named after the geneticist Gregor Mendel, who discovered a lot of interesting things. But we used to just think that there was kind of a two by two square you could do to figure out based on two parents what eye color a person will have. Yeah, which probably-

And it's much more complicated. Which probably led to a lot of incidents between people where it's like, hey, wait a minute, there's no blue eyes in our family. How is our kid blue eyed? Yeah, one source this week, it was a science writer talking about how another mom approached them at the park and said, oh, that kid's probably not your kid, right? And she was like, but they are? Huh? Like, what? And it was based on this eye color misinformation. Yeah. I do often approach people at the park and point to what is clearly their child and say, that's not your kid. Because that's a normal and pro-social thing to do. Your whole life is

some sort of Italian soap opera on TV. Like, just, that's not your child. And then a dramatic zoom on Katie and then a zoom on the other person. Exactly. And then as people have learned about genetics in general, people thought there's probably one gene that explains why eye color is this Mendelian thing, we think. It's a gene called OCA2 involved in making melanocytes, which are the cells that make our melanin in the iris of our eye and other parts too. So there was a theory that, oh, if this is like on or off as a gene, brown or blue eyes, and then you go from there. But then people kept looking at genetics and theorized 11 further genes

that might be involved. And then there's a landmark study in 2021, sampled nearly 200,000 people and theorized that 61 discrete genomic regions might be involved in generating the various eye colors. Because the biggest hole in the Mendelian thing is that there are colors besides brown and blue for human eyes. Yes. So... There's also different types of browns and blue, if you've noticed, and there's greens, there's hazels, there's gray, and there's even eyes that are nearly black. It's a whole spectrum of color. Yes. Yeah, even there's like lots of famous people,

besides we'll talk about heterochromia celebrities later, but there's just famous people with like an interesting eye color. Yeah. And then people proceeded to be like, anyway, there's two eye colors. Like, what, what are we doing? Yeah, what color are your eyes, Alex?

I can't see them through podcasting magic. The same, they're kind of hazel. Yeah. In various light they either look like a pale green or a pale brown, but they're hazel. Yeah. What about you? I can't see in this window.

Mine are blue. They're sort of a, I would say like a grayish blue, slight blue or whatever. I think green, either hazel or green is one of the more rare eye color, which is an interesting thing because people will say, oh, blue eyes are very rare. Blue eyes are actually not all that rare. A lot of people have blue eyes.

Brown eyes are most common, then blue eyes, then I think green and hazel and then other interesting variations. Yeah, right. There's a lot of blue eyes. There's apparently an internet myth that bounces around from time to time that blue eyes are going extinct. That's not true, that's not even a little bit true. It's just not true.

And that sounds racist. It's mostly, right, it feels like some kind of white nationalist thing, but it's also. Yeah, it really does feel that way. It's based on like a wild misunderstanding of that Mendelian thing. Yeah. So, it's...

No, that's not even... And apparently brown is the most common eye color in the world, but it's not going to take over the world tomorrow or something. No. It's not how it works. That is not how it works. Also, yeah, I mean, it is strictly speaking that the brown eye genes are a bit more dominant. The ones that will cause brown eyes are a bit more dominant than say blue eyes. But again, there's so much more complexity

that a lot of people have blue eyes and you can have brown eyes in your family and then have blue eyes. Exactly. Yeah. And this relatively new understanding of genetics, we're starting to figure out why. That study was in 2021 in the journal Science Advances. They also made sure to sample across ethnicities and across the world. They were really surprised to find at least 50 other genes that weren't previously associated with eye color. They also say only eight of those 50 genes have anything to do with the pigments in people in general that we knew of, like hair, skin, et cetera, because our eye color is pigments in the iris and then pigments in other parts of our bodies leads

to other visual attributes of people. And the distribution also of that pigment, like how much of it is there, how little of it is there, will vary the eye color. Yeah, right. That's how we get these ranges and stuff. Yeah. Another quick number there is two, because there are two kinds of pigments in the iris of the human eye.

There's one called eumelanin, which is sort of a dark brownish or black color, and there's one called pheomelanin, which is a orangish or yellowish light brown, even one source called it red. It's combinations of these two melanins in various amounts. That's why there's a range of eye colors. And generally speaking, when you have a lighter eye color, like either hazel or green or light brown or blue, you don't have as much of the darker melanin color, correct? Yeah, it's a lot of the visual appearance of the iris, the eumelanin. Right, right.

There's two types of coloration, strictly speaking, in the natural world. There's structural coloration and pigment. And structural coloration is basically how the light is refracted back. So like when you see like a prism and it goes through the prism and the light splits, it's kind of like that on a very small scale. And so you'll have a lot of, say, feathers or butterfly wings where you actually have structural coloration and that's the light being bent in a certain way such that it refracts a different wavelength. Pigmentation is the light hits it directly on, it absorbs all the wavelength except the one that you see,

which is shot right back at you. Yeah. Yeah, this is such a olive biology thing. Yeah, not just eye color. And that's right. You can maybe double check this just on the final cut of this, but I think that's the case. So eye color is actually a combination of both pigmentation and structural coloration.

So like with the pigmentation, that brown color, you know, the light is absorbed by the brown and the brown, the wavelengths that will eventually combine to form brown when it hits the back of your eye is reflected back at you. Whereas green colors and blue colors, there's not actually a green and blue pigment in your eye. As you mentioned, there's only the two pigments that account for the light brown, yellowish color and the dark brown.

And the blue and the green coloration are actually a result of structural coloration. So it's the way the light is bent and sort of altered. And then when it comes back to you, you see blue or green, but there's no actual blue or green pigment in the eye. Yeah, eye color in general is very cool and is part of, I think another reason heterochromia jumps out to us.

Like that can vary so much among humans where there's other variation we don't notice in this way. Yes. That's so cool. It's also why when you look at your eye up close, you might have blue eyes and you see little flecks of brown in there or you might have brown eyes and see little flecks of blue. It's the you will see variation even within your own eye. Oh no, my identity, my identity. I was just one eye color. No. Yeah, and then the other number this week is three.

That's too many eyes. Next number. What if I'm one of those third eye people, you know, that's what we reveal this week. Like I see with my third eye, man. Katie, your eyes are blue and the aura of your eyes are totally different than blue. But my third eye is on my butt, so all I see is the inside of my underwear.

Distracting, distracting for that to be a third of your vision. So there are three general kinds of ways that heterochromia presents in humans, like three ways it looks. And Katie mentioned some of them at the top, because according to the American Academy of Ophthalmology, when most of us imagine heterochromia, we're talking about complete heterochromia where one entire iris is a different color than the other whole iris. So like one eye looks brown, one eye looks blue, as an example. Yes.

Then there's a second type called central heterochromia, where there is an inner ring that is a different color than the outer rest of the iris. And apparently this is one common version is with green-eyed people, they might have like a yellowish or golden inner ring in one eye or both eyes I Think that like the outer ring if you have a dark ring sort of on the outer rim of your iris It's called a limbo ring How I know that but it sounds cool. I don't have one of those. I wish I did

I want to look like a husky There are people who have eyes like that You know how huskies have those really bright icy blue eyes and then they have that ring around their eyes. It's beautiful We're really drawn to different eyes. That's part of why this is a topic on people's minds and And then the third type to mention is called partial heterochromia Which is where part of one iris is a different color than the rest of the iris. It's often a thing where basically like one and a half of somebody's irises are one color and then another half iris or even a smaller portion like a pie piece shape is a different

color. That's so cool. That's so cool. That's awesome. Yeah. And some people mistake that partial heterochromia for like damage to the eye. And we'll talk about how both damage and genes can create a heterochromia. But if you're born with it, it usually means no issues. And most people born with heterochromia see as well as anybody else. Yeah, excellent. It's just a cool, fun thing you have with no consequences. Yeah, and I had never heard of that one in particular,

that like half of one iris can be a different color than the other half, like within that one eye. So cool. I wonder with people who have the complete heterochromia, there's a difference in sensitivity between the two eyes because I've heard this and I'm not sure how sort of scientifically proven or backed up this is, but that if you have lighter colored eyes,

sometimes you're more sensitive to sunlight. For me, sometimes if I see the sun is really bright, I'm blind, I can't see. And I've heard that if you have like a darker, a darker color that maybe less of the light is overwhelming your retina. So I don't know how true that is, but I'd be interested if someone, because then you would know for sure,

because you have someone who has the same brain, right? And if they, if they could close one eye and open the other eye and experience brightness or colors in different ways based on their iris color. Yeah, apparently it's a very minor difference, yeah. Oh really? That's cool. Like me, both my eyes are pretty light sensitive,

but it's because I have myopia and stuff, and my eye color is not playing a big role. And so, yeah, if people have a especially genetic complete heterochromia, there can be that slight difference, but you wouldn't really notice it or experience it. I see. Yeah. Interesting.

Yeah. And that potential thing and other things, it brings us into a big myth about heterochromia. It's time for a myth. Because takeaway number one, David Bowie is the number one global icon of heterochromia, despite not having heterochromia. Oh, he didn't have it, huh? But that's because it was a pupillary difference, not the actual iris, correct?

Exactly, yeah. Yeah, my dog, she had David Bowie eyes for a while. Don't panic, you guys. She was checked out by a vet. It was okay. She had some nerve damage from when she got bullied by this other dog. And so, yeah, and she survived. She had some stitches done, but after this dog attack, she had a little bit of nerve damage. So she had the David Bowie eyes where she had one pupil that was small and one pupil that was big.

Her eyes were brown, so you couldn't really see it very well. I mean, she still has it to some extent. She's still doing great. I don't know why I'm saying this in past tense, but she- Oh, it's cookie. Okay. Yeah. Yeah, cookie. Yeah, cookie. And she, but yeah, it didn't seem to bother her at all. But yeah, that was due to some nerve

damage where one of her pupils remained slightly more dilated than the other one. Okay. Yeah. Yeah, this fits Bowie. He had a dilated pupil due to an injury. And he had it for his whole life after the injury at age 15. It's a condition called anisocoria. Then people have gone on to believe he had heterochromia. Even after his passing, he is the most famous example of heterochromia in the world in like popular culture, but it's not what he had. Right, right, right. He had two blue eyes and one dilated pupil. Yeah, I mean I could kind of see though if you see the pupil if you don't register it

as being a larger pupil one eye could look a little brown, but yeah that's interesting. Right, yeah. Yeah. Yeah, we all kind of convinced ourselves cookies David bow wow wowie Key sources here are an essay for the conversation calm by Kevin hunt senior lecturer in design and culture at Nottingham Trent University Also a piece for the Daily Dot by Kristen Hubby, and health resources from the Cleveland Clinic. I hope I said earlier, we are not doctors and we will also just cite the best health resources we can about heterochromia. If you're like, hey, my eye is suddenly looking or feeling weird or my pupil is suddenly really large, go to the doctor ASAP.

Yeah. You shouldn't have fired this up to listen to it for an hour and wonder. No, no, no. That was weird. No, because actually that is one of the things, like if you have a difference in pupil size and that's not normal for you, that's something to go to the doctor for because that could be a whole bunch of things, some of which could be really urgent. Totally.

And this David Bowie story is a clear one. He had irises that are the same color, but like we were saying, one very dilated pupil, especially with blue irises, a lot of people just visually received that as his eyes are different colors. Right, right. And David Bowie was born with two blue eyes. Bowie is a stage name. He was named David Jones at birth. Mm-hmm.

And when he was 15 years old, David Jones got in a fight with his friend George Underwood. They both wanted to date the same girl. Mm. And they just started hitting each other in the eye nerves. The story apparently was sort of a sucker punch and out of character for George Underwood. He just suddenly punches David and the punch scratches David's left eyeball resulting in paralysis of the muscles that contract the iris.

Interesting. So he had a permanently dilated left pupil for the rest of his life. And that's called anisocoria. And the girls all thought that was really hot. And then so he started to get even more girls and Underhill... Underwood. Underwood, sorry. Underwood didn't get any girls because he's just an eye puncher.

Right. Next, Underwood forced David Jones to work out a lot. Oh, no. He's handsome earth. Then he got him cool shirts Oh, no, he's handsome Squid it's handsome Squidward all over again And yeah, and this this uneven dilation of the pupils it did also impact David Bowie's vision, unlike most heterochromias. I'm like heterochromia, right. Because the iris doesn't have as much of an impact on your vision, if at all, versus the

pupil itself. Exactly, yeah. So this left eye with a dilated pupil, his vision was different, death perception was different. It was more light sensitive. It also made that eye more prone to the condition we call red eye. If her eyes are dried or tired,

that increases the occurrence of it. And then on top of that, David Bowie is up late at night doing drugs. Also some of his makeup, and especially like the Aladdin's sane era, there's red, just eyeshadow. So like people saw a lot of eye difference. Yeah.

That one had more of an effect. Yeah, you know. The drug stuff. Again, we're not doctors, but maybe no cocaine in Berlin, you know? You can skip that. I don't prescribe cocaine in Berlin to you, the listener. What else are you supposed to do in Berlin if you're not going to do cocaine? House music, you know, anyway.

So there's a lot of good news with this eye injury. Bowie could still see pretty well. He wasn't like impaired to an extent that it made much difference. And also he and George remained close friends. We're in bands together and they only stopped when George said he was going to focus his time on visual arts and graphic design. And George Underwood did the art for two David Bowie albums. He did the cover of Hunky Dory and he did the cover of The Rise and Fall of Ziggy Stardust and The Spiders from Mars. Oh yeah, that's a pretty iconic one, right?

To me, they both are. I'm a big Bowie fan. And yeah, they like, the guy who gave him this dilated pupil did some of his most famous album covers. It's wild. Yeah. Yeah, it is interesting. I can definitely see from this photo of David Bowie how people would mistakenly perceive

that he has heterochromia because when you have one, when his head especially is at an angle and you have the light hitting it from the side, one eye looks quite a bit darker than the other one. That's right. Yeah. And again, another reason for it is this isn't an album cover by George Underwood, but the album Heroes, it's a photo of David Bowie and it's a black and white photo. So that makes it look even more like it's maybe his eyes are different colors. Yes. Yeah. No, I can totally see that because the pupil is quite wide and it swallows a

lot of that eye. It's such a big visual difference. And decades later, Bowie publicly thanked Underwood for the injury. It's that it gave him, quote, a kind of mystique. Because a few years before his death- Punch your friends pretty, guys. That's the lesson. Punch your friends pretty. Apparently a few years before his death, Bowie told an interviewer that he grew up

as, quote, plain old David Jones, a middle-class boy from London's suburbs, end quote. And he credited this 1962 eye injury and then a name change to David Bowie later in the 60s as like the two beginnings of him having a lot of personas in his career and seeming like more of a celebrity than a regular kid from the suburbs. Yeah, because part of his whole persona, at least professionally, was being kind of strange, being interesting, being alien and weird and alternative. Yeah, and his eyes automatically did a lot of that. Yeah.

Yeah. And so, yeah, he is now the most famous heterochromia case in the world without having it. Yeah. And there's a few ways Bowie's a particularly confusing case, because one is that you can develop a heterochromia from an eye injury. Really? It's just that his specific injury did not cause it. Because apparently some people debunk this by saying, heterochromia can never be from an injury.

And that's not quite true either. The Cleveland Clinic says that there's several different injuries and medical conditions that can cause it besides genes. One common condition called Horner's syndrome causes underlying nerve damage in one side of the face. And then one result of that is that the cells producing melanin in one eye don't get the stimulation they need to like do their job. And then you have had a chromia. Huh. As far as I understand it, that must either happen in childhood or be something that takes quite a bit of time because with a lot of cells

in the eyes, I thought that they were quite slow to renew versus say the cells in your skin. Yeah, it's usually a long process. It's usually a very small difference. Right, right. Apparently some treatments for glaucoma can cause heterochromia. A physical blow can in a way do it, but we just had a different pupil problem.

So that also makes this very confusing. It's an incredibly specific way he didn't have heterochromia. Right. Why do colored contacts for your cosplay when you just can have a buddy punch you in the eye a few times until something starts looking good? Not a doctor. Definitely not a doctor. It's like what Happy Gilmore gets ready for hockey season by just having pucks shot at him.

Yeah. Also apparently you have to be careful with colored contacts because those can actually scratch your cornea and cause cornea damage so it is not actually clear what's safer. And then the other confusing thing with David Bowie is it turns out a lot of other celebrities have heterochromia, in particular actors who are people we look at like all the time. But the thing with real heterochromia is it tends not to be as visually grabby as this thing Bowie had. And so we just don't notice it. And it's not always say a really light blue eye and a really dark brown eye, correct?

So it's not always going to be that, I guess, dramatic. So you might have one eye that's brown and one eye that's hazel. It might be kind of hard to tell the difference. Exactly right. Apparently Dan Aykroyd has a brown eye and a hazel eye. So like one of the Ghostbusters has had had a real chromia this whole time, but it's not very noticeable. It doesn't, it looked like David Bowie's face. I'm looking at photos. I'm opening up my folder of Dan Aykroyd photos that I have on my desktop. Take a look at his eyes, deep into his eyes.

Katie, we're getting a lot of noise from your Dan Aykroyd hard drive that you plugged in. It really has a loud fan. Yeah. Sorry. I have like five terabytes of Dan Aykroyd photos. Okay, cool. Yeah, no, I can see that. Yeah, and then Kiefer Sutherland has a blue eye and a green eye.

And then Mila Kunis has a green eye and a brown eye. I've seen her in a lot of sitcoms and movies, never noticed. I have never noticed that. And then Kate Bosworth has partial heterochromia. She has two blue eyes, except that one of the blue eyes has a hazel portion. These are all people who've been on screens a lot and nobody thinks of them like we think of David Bowie. Yeah.

Now, I see it with Mila Kunis. It's just very subtle. Been there the whole time. I just never noticed. Yeah. So any of these people, again, that's Kiefer Sutherland, Mila Kunis, Kate Bosworth, Dan Aykroyd. Those are just some of the examples.

I didn't keep going. But you can just Google them and see it. And it's been hiding in plain sight. I'm opening up my Kiefer Sutherland folder. Yeah. Kate Bosworth is a separate PC probably. You need to go into your annex. Hang on.

Let me get my other hard drive. Yeah. Hang on, let me get my other hard drive. But yeah, like Bowie's different thing is a lot more noticeable. And so that's why people associate him with it. And in researching him, I found two wonderful examples of the massive worldwide cultural footprint of David Bowie's perceived heterochromia that he doesn't have. One is that there's a minion referencing it. One of the minion characters.

From the Despicable Me franchise. Oh, I've never heard of minions. So what are they? They're a meme that holds our entire culture together. Yeah. I really like the minions too. But in especially the minions movie there's three key minions.

And one of them named Bob has had heterochromia this whole time. Oh. He's drawn with a realistic green eye and brown eye complete heterochromia. Yeah, I'm looking at him. And a lot of their body is the eye, you know? Like it's kind of prominent when you see it.

I really am fascinated by minion anatomy. Because, yeah, because you know, I've got to think like how much, you know how you can, with an owl, their eyes are so big that when you look into their ear hole, you can actually see the back of their eye because their eyes are giant. You know that? Yeah. It's wild. So I'm just thinking about how much of this minion's skull is taken up by eyes. Also with, I think they're called, what are they called?

These little tiny lemurs. And they're called mouse, not mouse, pygmy lemurs. Let me see. The minions of the trees? Yeah, sure. Yeah. There are certain lemurs eyes eyes are so big that they can't actually rotate their eyes and They like move their entire head instead

But with the minions with the minions, I can't see them. They don't have a neck So i'm trying to figure out I don't think i've ever seen them rotate their eyes either, because I don't think that would necessarily be possible because their skull's not big enough to facilitate the rotation of their eyeballs. So they must turn their entire bodies to be able to see in different directions. It's kind of part of their antique vibe. It's a lot of hopping and shuffling. You can confirm that for me though, that that's how minions have to turn their entire bodies

to see in different directions. I think I can tell the story. I met someone once who works for the company that makes the Despicable Me and Minions movies. And I told them that I like the Minions and they thought I was lying and messing with them. I really do enjoy that Minions movie is awesome, and it's just good, but no one believes me, because it's also kind of made fun of, yeah. That's some confirmation for me that the Minions are a Psy-op

to try to see how much something... fairly innocuous, right? Because I don't find them movies inherently annoying or anything. Just movies. There was one day where there were no minions and then the next day where minions were absolutely everywhere. That does seem like your friend is tacitly admitting that the minions were meant to be a psychological form of warfare. And he's genuinely surprised that someone could withstand that and come out on the other side enjoying it. I like the idea that they were one very specific CIA objective.

It was just to build support for one congressional farm bill or something. And then it got way out of hand. Too late. But anyway, so there's one minion who's always been drawn with realistic, complete heterochromia. And according to press interviews, that's because Despicable Me co-director Pierre Coffin loves David Bowie and believed the myth that David Bowie has heterochromia. So then they depicted a minion with actual heterochromia in the animated sense. Because the minion actually has the different iris colors which is the signature of heterochromia. His pupil sizes are the same. Exactly like David Bowie's reputation led to a minion with a more realistic heterochromia.

Right. It's so weird. The other amazing footprint is a koala. In 2016, The Guardian printed this headline in The Guardian, Face Oddity, David Bowie of koalas rescued by Australia Zoo staff. Face oddity, right? This was in the Brisbane area of Queensland. Rescuers found a koala that had been injured by a motorist. But luckily it only injured the leg. They were able to put a cast on the broken leg and it healed and they released the koala back into the wild. Cutie. In the process they discovered this was a female koala with one brown eye and one blue eye.

Koalas can have heterochromia. Yeah, she's stunning. And they named her Bowie because even with a female koala they said David Bowie is the top celebrity. We got to do it. Well, David Bowie did a little bit of gender fluidity there, so no harm, no foul. Yeah, it works. And yeah, according to Zoo veterinarian Sharon Griffiths, quote, Bowie's heterochromia doesn't affect how she sees the world around her. In fact, her eyesight is great, exactly what we like to see in a young koala, end quote. So even with koalas, genetic heterochromia usually no impact on vision.

Yeah, no problem. And also all they have to do with their vision is see leaves and maybe eat them. And then nap. That's the koala lifestyle. Yeah. I mean, she's up late making a trilogy of albums in Berlin and having too much leaves, you know? We're worried about her. But yeah, and also shout out to The Guardian, their article about Bowie the Koala made a

point of mentioning that the human David Bowie had anisocoria and did not have heterochromia. Like they did the journalistic work. I really appreciate it. Right. Really, really defeating those lies about our dearly beloved David Bowie. Yeah. He was also not a koala. People didn't know this. People thought he was because of all the eucalyptus leaves he would eat, but that was actually just his own kind of personal quirk. Ziggy ate his leaves, spooned up files and climbing eucalyptus trees like a koala from

Australia. Amazing. Amazing. That's a lot of biology and pop culture with heterochromia. We're going to take a break then come back with more medical science and finally dogs. Dogs! Dogs. Folks, we're back and we're back with takeaway number two.

There is an underground industry for surgically undoing heterochromia. I don't know how to feel about this yet. And again, we're not doctors, but the doctors I looked up do not recommend it. Okay, then I'm against it. Unless they really improve the technology or license it more in the United States, there's not a bunch of solid reasons to recommend it if it's cosmetic. It's really not my place to tell people what to do in terms of cosmetic procedures if it's safe, right?

If it doesn't have that many side effects or anything. I really think natural differences between people are really cool. So it makes me feel, I don't know. Like again, it's not my place. Like if someone really wants to do something with their body, right? And it would make them feel better

and there's not a lot of external pressure to do it, then I shouldn't be against it. But if people are doing that because they're bullied about their heterochromia, then that's. Yeah, and yeah, apparently one broad solution to that is colored contacts or colored contact anyway. Right. This is not FDA approved to have surgery

to change your iris color, and the limited amount of public reporting suggests it's risky. The one main story we have here is from a New York Times piece in 2013 by Abby Allen. That story, they covered someone who simply wanted to make her eyes match. It's a patient named Anita Adams, resident of Colorado with one brown eye, one green eye. And she started Googling around in 2008 about ways to make her eyes matching color besides colored contacts. And quoting the Times here, she found a company New Color Iris marketing a device invented by a Panamanian ophthalmologist, Dr. Alberto

Del Rey Khan, that could apparently implant an artificial or prosthetic iris over her natural one. The device was not approved by the Food and Drug Administration, nor were there any clinical studies or peer-reviewed publications about it, but Ms. Adams found Facebook posts and YouTube testimonials from patients whose eyes had gone from drab brown to an icy blue and were thrilled with the results." End quote. Drarab brown. Now hang on a minute. Brown's great. Yeah, I love brown eyes. To me, they're so warm and beautiful that I object to that. I love blue eyes too and all the other eye colors, so there's no eye primacy here, but yes. I think unfortunately though, our society does often

elevate say lighter colored eyes, which I think is probably part of this greater trend of colorism, right? Where it's like lighter features are elevated as beauty, even though there's no, it's completely subjective. There's no reason for that other than culture. Yeah, exactly. And it seems like part of why this is potentially unsafe is that there hasn't been a lot of

medical need to change it. No, yeah. The one thing to mention here about medical need is that some people need iris surgery for actual medical reasons, and then that can end up altering the iris' color. One example is a kind of cancer in the iris, sort of like a skin cancer, but just a melanoma in the iris. If they do surgery on that, that can lead to a different iris color.

Some people also receive chemo in their eye. The chemo can change the iris's color. Some glaucoma treatments involve prostaglandins that darken the iris a little bit. And a few people are born without an iris. It's a condition called aniridia. Sources here are a piece for theconversation.com by Adam Taylor, professor and director of Clinical Anatomy Learning Center, Lancaster University, and also work by Hank Green on the SciShow channel. They say that as of July 2024, the US FDA sort of allows surgeries to implant an iris for aniridia. They don't approve it, but you can seek what's called compassionate approval if someone's in serious pain or has a life-threatening

issue. Right. Okay. Surgeons have developed ways to implant an iris. And then people in this New York Times story who are literally fly-by-night operations are doing it for just cosmetic stuff. I try to hesitate to judge before someone does a cosmetic surgery because I don't know what their situation is. I don't know what they are doing it for, right?

So someone can have a whole bunch of personal reasons to want to change something about their appearance. And that's not really for me to make a judgment on. But if it's something where, say, someone is getting like bullied for a part of their physical appearance that they can't help, but it's perfectly healthy. And then the surgery itself is not necessarily healthy. That definitely makes me uncomfortable.

Yeah. Yeah. And I wish we had more reporting around people's experiences with this because the one story here about Anita Adams goes poorly and that's all we've got. Oh no, I'm sorry. She reads about this treatment by this Panamanian ophthalmologist, wires them several thousand dollars, flies to Panama and receives a procedure to implant an iris on top of her iris. It took 15 minutes. She was told there were no risks other than a slight possibility of glaucoma And then also she went on a TV show in the US called Inside Edition Which I don't know if people seen it. It's like vaguely newsy, but not

It's like news had sort of a burp and then that's Inside Edition They like did a little piece about her talking about how much she loved the results of that and then this company new color Iris paid her $500 for doing that. So I don't love people being paid to talk about their medical elective procedure like that. And then the bad news is about two years later, fall of 2010, Adam said her vision grew spotty. She was, quote, scared to death. I was going blind.

And then when she tried to contact this doctor as well as their company headquartered in New York, there was no response. And then when she went to the website of New Color Iris, it redirected to a different brand and domain called brightocular.com. So they kind of pulled up stakes like a carnival scammer. Oh no. So did she lose her vision in that eye? She says that she was able to have like a quick necessary surgery to remove the implant. Her vision has not recovered but is still somewhat functional. I see. I see.

And also her eye is a different shape now. Oh man. And yeah, according to this professor Adam Taylor at Lancaster University, iris implantation complications can include infections, changes of shape to the eye, and if it's drastic, blindness. And yeah, and then also Adams looked into this bright ocular thing. She just contacted them under a different name to ask what they do. And it was the same procedure, but you fly to Istanbul instead of Panama. And like different testimonials claims about soon it'll be approved in Europe. It's just, you know, we're just working on it kind of thing.

And the New York Times says bright ocular denied any relationship to new color iris. But the New York Times found trademark registration records linking the two. So it's like definitely a scheme to me. But yeah, so we're not doctors. The technology could improve. Like, years from now, this could be awesome, but it seems to not be awesome. I don't think we need to preface us saying it's probably not a good idea to go to a sham company to get a non-approved surgery on your eyeball with, we're not doctors. We are also people that can just read the news. There is a world of changing heterochromia if there's some kind of significant problem,

but the vast majority of people, it's just a different color of virus. If you're not sweating it, leave it. It's great. It's cool. Yeah. I mean, I think it's stunning, but it doesn't matter what my opinion is. It matters what you see in the mirror, which I hope is your pretty face. Yeah, I agree. Yeah.

And also like moving on to our last takeaway, we've got a joyful takeaway about another celebrity. I think I know who this one is. Takeaway number three. The most famous athlete with heterochromia makes a point of rescuing dogs with heterochromia. Yay! And this is the David Bowie of heterochromia for sports, but they actually have heterochromia. It's a baseball pitcher named Max Scherzer.

Yes. Max Scherzer. I think I saw him playing. I don't watch a lot of baseball, but my father-in-law loves baseball. So we went and we saw some baseball with my father-in-law and I think he was playing that day. Is he a Washington Nationals fan? Yes.

Max Scherzer won a World Series with the Washington Nationals. Yay! That's not what we watched, but yes, we watched and we saw him. Yeah. Yeah, he is almost definitely going to be a Hall of Famer as soon as he's eligible. You have to retire first and he's still playing. But Max Scherzer is one of the best pitchers of the last 20 years. Two World Series championships, three Cy Young Awards.

And he's also famous for his demeanor on the mound. In 2019, he went viral for shouting no at his manager when his manager tried to substitute him after he'd already thrown 117 pitches. for shouting no at his manager when his manager tried to substitute him after he'd already thrown a hundred seventeen pitches and He convinced his manager to let him throw three more pitches with his hyper intense in a positive way. No, I'm still pitching And and we really zoom in on the attributes of athletes to extreme detail and people have noticed that Max Scherzer has a brown left eye and a blue right eye. So when he's making these wild faces at his manager, he also has distinctive eyes. Unlike some of the other celebrities with heterochromia, you can really tell for him. It's very, very striking.

Yeah, the brown blue combo and the way it looks with him specifically. Exactly. It's just more noticeable than Mila Kunis. Very cool. Yeah. Because especially he's doing sports faces and like, I just struck out someone erotically faces. You can see. Yeah. Or staring at his catcher while he's considered to be overly intense in a positive way. After the game, he'll be normal, but during the game he's like, ah, I'm gonna try to throw a complete game. He's led the league in complete games

three different seasons. Like he's seen as a real competitor with his wild heterochromia eyes. Do you think batters ever just get lost in his eyes and he strikes them out? It's why they should have like Frank Sinatra pitch, you know? Right. Like, oh, old blue eyes striking out a Babe Ruth, I guess.

It's not quite the same era. Anyway. And Scherzer likes how he looks. In an interview with NBC Sports, he said, quote, I've always celebrated it. Whether you like it or not, that's who I am. I got one blue and one brown. There's nothing I can do about it. I love that.

And then the other fun thing that we'll link pictures of, especially from Yahoo Sports, when he's off the field, Max and his wife Erica love to rescue and foster dogs. And they have tended to make a point of dogs with heterochromia. So then you have pictures of Max Scherzer with a dog whose eyes are like Max Scherzer. It's really great. That's fun. That's some fun stuff going on there. Yeah, I'm looking at these dogs. It's great. It's really good. I wonder if these dogs also, they're out playing catch and then he's like, all right, time to come in dogs. And the dog just goes, no. I also want them to have little hats on now, you know? Just baseball stuff.

Yeah, little hats. These are beautiful. These are beautiful dogs, by the way. Yeah, as of 2022, they had three heterochromic dogs that are their forever dogs. Their names are Bo, Raffi, and Rocco. And then they've fostered a lot more. In 2015, Max did an ad for Washington, DC's Humane Rescue Alliance with a foster dog named Glee. And both of them have heterochromia and you could tell side by side and stuff. And apparently that got Glee

adopted within days. It's just cool. That's what he's doing. And I think it's interesting because yeah, dogs and cats, I think think tend to have heterochromia at higher rates than humans. Yeah, apparently. There's all sorts of weird, interesting genetic linkages that happen with animals and when you domesticate them. So for instance, doggy ears are floppy because the cartilage is actually, the cartilage production is related to these neural crest genes that are altered in domesticated dogs, just through selection.

We select dogs that are more puppy-like, friendly, less aggressive, less frightened of human contact and that alter these neural crest cells that are involved in the dog's development from an embryonic stage. And those also happen to diversify into cartilage producing genes. So that's why you have a lot of domestic animals that have floppy ears who are also domesticated. And there are these links that are only there because of the proximity of the genes on the genome. And it doesn't necessarily have anything to do with like a dog's behavior being friendlier, right? It just happens they happen to be linked. So it's a similar thing with maybe other alterations in terms of genetic selection, meaning they're more likely to have heterochromia.

Yeah, that's a great parallel. I also tried to Google, couldn't find anything. It doesn't seem like people have had a culturally negative or positive vibe around heterochromia in dogs. It just kind of happened, like those floppy ears. Although floppy ears we kind of like, but yeah, it's just something that's happened along the way in our creation of a domesticated dog population. And also dogs have different genes than us. Maybe they're more prone to it. We don't really know that it hasn't been like studied, studied. What I mentioned at the top of the show is the link between blue eyes, specifically in white cats.

I don't know if this is the case also for white dogs, but in white cats at least, the link between the blue eyes and the higher probability of deafness and then also the higher probability if a cat has heterochromia and one eye is blue and they also have the white coat that the blue eye is gonna be next to an ear that's deaf like there's a there's a higher probability of that which is very interesting. That is yeah and I think

also we just noticed this so much in dogs, cats, horses because those are some animals we really think about a lot when we domesticate one and have one. Yeah. Like, oh, my horsey has heterochromia is a thing people have said, you know. Although you have to like for a cat and a dog, they have the forward facing eyes, so you see it right away with a horse, you kind of have to go from one side and to the next side and go like, wait a minute, let me go back to that first side. Oh, yeah. Gathering your farm community like it's a barn raising, but for checking your horse's eyes for heterochromia. Now you look on that side and I look on this side and you tell me what you see.

I'll do it for you later. Like this is a weird community. But yeah, and so if you want a new favorite heterochromia celebrity, especially if you're not a sports fan, didn't know, Max Scherzer still pitches for the Toronto Blue Jays at the moment. Oh, really? He may retire soon. He's getting up there. But yeah, he's the famous guy. Wait, is he American or Canadian? American, yeah.

But he switched allegiances to Canada, huh? Hang on, you can just do that? In baseball, there's one Canadian team, the other 29 are in the US. I got to learn how to play baseball. Yeah, let's see if the Tarantablices need a Katie. Yeah. I can't throw, I can't pitch, and I can't bat, and I'm not the best runner, but I got a lot of spunk. And sports movies tell me spunk is like 99% of success. We'll just do exactly the plot of that movie,

Rookie of the Gear. Like you'll break your arm, but then it's super powerful for pitching. There's no rules in baseball that specifically say Katie can't play baseball, so. Checkmate baseball. Checkmate. So, uh... Folks, that's the main episode for this week. Welcome to the outro, with fun features for you such as help remembering this episode, with a run back through the big takeaways.

Takeaway number one, David Bowie is the number one global icon of heterochromia despite not having heterochromia. He has a dilated pupil from an injury, it's called anisocoria, and he has blue eyes. Also a thing I love within that, the friend named George Underwood who gave him that injury went on to design two of his album covers and be a close friend, really great.

Takeaway number two, there is an underground industry for surgically undoing heterochromia with unlicensed iris implants. Takeaway number three, Max Scherzer, the most famous athlete with heterochromia, makes a point of rescuing dogs with heterochromia. And then a lot of numbers this week about the genetics of heterochromia, the different ways heterochromia can present also the false Mendelian belief about human eye color. Those are the takeaways. Also, I said that's the main episode because there's more secretly incredibly fascinating stuff available to you right now if you support this show at MaximumFun.org.

Members are the reason this podcast exists. Some members get a bonus show every week where we explore one obviously incredibly fascinating story related to the main episode. This week's bonus topic is bilateral gynandromorphism in animals. A cool thing that can have different eye colors, but is also totally different. Visit sifpod.fund for that bonus show, for a library of more than 20 dozen other secretly incredibly fascinating bonus shows, and a catalog of all sorts of Max Fund bonus shows. It's special audio, it's just for members. Thank you to everybody who backs this podcast operation. Additional fun things, check out our research sources on this episode's page at maximumfund.org. Key sources this week include all of the expert medical information we can gather, especially from the Cleveland Clinic, from the American Academy of Ophthalmology,

also a key study in the journal Science Advances published in 2021. We're also linking journalism from The Guardian, from The Daily Dot, from The New York Times, and expert interviews, especially from Adam Taylor, professor and director of the Clinical Academy Learning Center at Lancaster University, and then in a pop-cultural way, Kevin Hunt, senior lecturer in design and culture at Nottingham Trent University. Really wonderful write-up of the life of David Bowie and his eyes. That page also features resources such as native-land.ca.

I'm using those to acknowledge that I recorded this in Lenapehoking, the traditional land of the Munsee Lenape people and the Wapinger people, as well as the Mohican people, Skatigok people, and others. Also KD taped this in the country of Italy, and I want to acknowledge that in my location, in many other locations in the Americas and elsewhere, native people are very much still here. That feels worth doing on each episode, and join the free CIF Discord,

where we're sharing stories and resources about native people and life. There is a link in this episode's description to join the Discord. We're also talking about this episode on the Discord, and hey, would you like a tip on another episode? Because each week I'm finding you something randomly incredibly fascinating

by running all the past episode numbers through a random number generator. This week's pick is episode 149. That's about the topic of narwhals. Fun fact there, the narwhal tusk is something that we have theories about. It is probably a way male narwhals attract females. So I recommend that episode. I also recommend my co-host Katie Golden's weekly podcast, Creature Feature, about animals, science, and more. Our theme music is Unbroken, Un-Shaven by the BUDDHOS band. Our show logo is by artist Burton

Durand. Special thanks to Chris Souza for audio mastering on this episode. Special thanks to the Beacon Music Factory for taping support. Extra extra special thanks go to our members and thank you to all our listeners. I am thrilled to say we will be back next week with more secretly incredibly fascinating. So how about that? Talk to you then. Music Maximum Fun, a worker-owned network of artist-owned shows, supported directly by you.