What Greenland Sharks Are Teaching Us About Aging Eyes

Greenland sharks' eyes never seem to get old. Plus, exactly how flawless is the greatest eye in the sky, the James Webb Space Telescope?

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Speaker 00

  WNYC is supported by Bear. Science is about asking questions, testing, trying again. It's not easy, but it's relentless. It evolves, and that's why science delivers. Learn more at sciencedelivers.com.

• 0:14Ira Flatow?

  Science Friday is supported by MathWorks, creator of MATLAB and Simulink software for technical computing and model-based design. MathWorks, accelerating the pace of discovery in engineering and science. Learn more at mathworks.com. Hi, this is Science Friday. I'm Ira Flatow. Today on the show, eyeballs. As we age, all sorts of things can go awry in our eyes. Our vision gets blurry, cataracts may make our eyes cloudy, and we're more at risk for diseases like glaucoma. So how do we keep our eyes healthy for longer?

• 0:54Ira Flatow?

  According to new research published in Nature Communications, one clue may lie in the eyeballs of, you're gonna guess this, the eyeballs of Greenland sharks. These sharks can survive for more than 400 years. And because they live for so long, and their eyeballs look glazed over, scientists thought they were basically blind. That is until this new study found that the shark's eyes are healthier than we originally thought. So, how can Greenland sharks maintain their healthy eyes for so long? And can it tell us anything about preserving our own eyesight? Joining me is the study author, Dr. Dorota Skovronskaya-Kravchik, Associate Professor at the University of California, Irvine,

• 1:39Ira Flatow?

  who studies the mechanisms of aging. Welcome to Science Friday.

• 1:42Speaker 02

  Yeah, hello. Thank you for having me.

• 1:45Ira Flatow?

  Nice to have you. So what is it about Greenland sharks that caught your eye, so to speak?

• 1:51Speaker 02

  Yes, there was a study in 2016 in Science, so very good journal, talking about how long shark can live. And they found that these sharks can live, as you said, over 400 years.

• 2:09Speaker 02

  But at the same time, uh, they uh, released a lot of movies and the movies were really cool. I mean, you know, they were like people swimming along the shark and filming them. And what I noticed is that the sharks are observing the swimmers.

• 2:25Ira Flatow?

  So they're looking back at the swimmers who are looking at them is is what you're saying.

• 2:28Speaker 02

  Exactly. They were following them with their eyes. Well, that was just first observation. So I was really, I mean, for me as an eye lover, it was very interesting and so on. And then I read the paper carefully and I realized that there is a strong assumption that those animals do not see. That was weird for me because they were definitely following the light especially.

• 2:50Ira Flatow?

  Uh, your aha moment there. Yeah.

• 2:52Speaker 02

  Yeah, that was surprising. And then um, the occasion came when we realized that we can actually contact the scientist there and ask if they still have some leftover eyeballs from their studies because uh, they collected some eyeballs exactly for the carbon dating, which they did on lens.

• 3:12Ira Flatow?

  So what did you do? Just order up a box of shark eyeballs here?

• 3:16Speaker 02

  Something like this. Well, of course, we wrote to them a nice uh, uh, nice message and asked if they are interested in collaboration. And they said, yes, sure, we can send you some eyes we have in freezer, but we can also collect some more eyes during our next trip.

• 3:33Ira Flatow?

  Wow.

• 3:33Speaker 02

  That was amazing.

• 3:34Ira Flatow?

  So please describe what these eyeballs look like for me. Spare no details here. I wanna know exactly.

• 3:40Speaker 02

  Well, they are quite slimy. They are quite slimy. So when we get them, they are frozen and usually. And first of all, they are size of the, let's say, small apple or big plum, you know?

• 3:56Ira Flatow?

  Wow.

• 3:57Speaker 02

  So they are pretty big. And then uh, when we get them frozen, we don't wanna uh, lose the specimens. So what we do, we actually cut them with the little thin saw in half.

• 4:07Ira Flatow?

  I'm cringing. I'm cringing.

• 4:11Speaker 02

  I know it sounds like that, but you know, we don't want to spare material. Those animals are living so long and we want to be sure we study everything we can with with the material we have.

• 4:22Ira Flatow?

  So what's it like once you get cut, you cut through it? What's it like to do that?

• 4:26Speaker 02

  Well, it's just, it's like ice, right? It's frozen, so it's like cutting through ice. But what is really amazing, when you open, you just see cross section, you know, like through the eye and it's see how beautiful, how big it is and also how protected it is from the pressure. There is a very thick walls around, so the eyes not collapse when they are deep in the sea. It's it's just already, you know, like amazing. You just already see that there are adaptations to how they live and where they live. So it is a low light detecting. Um, so there's no really high resolution, but they definitely see uh shapes passing by, a light passing by, and of course, uh, probably see if there's big, small, and so

• 5:11Speaker 02

  on, so on.

• 5:12Ira Flatow?

  But and of course, with these sharks, living up to four hundred years, I would expect that when you cut open the eye, you might see aged things like we have, like cataracts and signs of aging, but you didn't see that, did you?

• 5:26Speaker 02

  So that's the surprising part. There is no signs of the deposits behind the retina. There is no signs of some degeneration of the part of it, uh, some cells disappearing. Everything looks very uh organized and ready to go, ready to work.

• 5:43Ira Flatow?

  As opposed to that happening in humans?

• 5:46Speaker 02

  Yes, yes.

• 5:46Ira Flatow?

  As we get older.

• 5:47Speaker 02

  Exactly. When you start to look at the human eyeballs, uh, which we fortunately receive from donors, um, we can see already like around forty, fifty years old donors, we start to see some deposits, some debris, some, you know, things in the eye that we can presume they were already disturbing a little bit vision, but then with sixty, seventy years old eyeballs, now we start to see plethora of different uh problems.

• 6:15Ira Flatow?

  So what what is, what is it about aging that our eyes fall apart as we get older? What's going on there?

• 6:22Speaker 02

  I don't wanna be, uh, I don't wanna be pessimist, but actually we all fall apart.

• 6:29Ira Flatow?

  Everything falls apart, not just your eyes.

• 6:31Speaker 02

  Not just our eyes. Our eyes seem to actually work pretty well for a long time and they have really a lot of mechanisms to resist the stress. But what seems to happen is that our eyes are exposed to many different small stresses, impacts and challenges through their life. And they always have to repair themselves. So there's always a little bit damage, repair, damage, repair. But you know, if you have it so often, sometimes the repair will not be perfect, right? Or sometimes the mechanism of repair is not efficient in given type of damage.

• 7:13Speaker 02

  So that's why with time, you know, the system is less and less resilient or more and more susceptible to next stress. And this is how it happens, you know, with time, the

• 7:27Ira Flatow?

  Right, right.

• 7:28Speaker 02

  Tissue goes mad.

• 7:34Ira Flatow?

  Tell me about it. I'm a direct witness to that. Well, what is it? And I guess this is what you would like to know. What is it about the Greenland sharks that they can prevent all of this? Is it something genetic, do you think?

• 7:47Speaker 02

  So, yes, so there are two things that we think happen. First of all, the environment is really cold, so it slows dose metabolism. But then we looked into the, more into molecular biology of these eyeballs and we realized that at the molecular level, they seem to have very efficient, highly expressed or highly present DNA repair mechanism, which means there is a push to keep this vision healthy longer.

• 8:22Ira Flatow?

  Do we have the same gene mechanism that maybe is not expressed?

• 8:27Speaker 02

  That's actually beautiful question. We have exact same mechanism. We have exact same genes, but maybe they are not expressed highly enough. So one of those genes that we shown, we have studied a little bit before. So we know already that this mechanism is crucial. But now we have a proof that if you actually turn it up. It may be protective.

• 8:53Ira Flatow?

  So what we need to do is figure out how to hack the Greenland shark's eye-saving method and its genetics and possibly use it for a treatment for us?

• 9:03Speaker 02

  That would be the simplest translation, right, of the findings. And obviously, it sounds like that. We have to test it very much. But I do think that if we can increase the efficiency of the DNA repair mechanism, we actually may be able to protect vision longer. So now we are, we started many different experiments to think about it creatively, how we could really bring it to human.

• 9:31Ira Flatow?

  What, where do you go from here?

• 9:33Speaker 02

  Yeah, thank you for that question. So what our laboratory is interested in is to really use the knowledge about the DNA damage repair mechanism and how it's boosted in the shark eye to try to understand whether we can do the same first in mammals, so like in mouse, and then hopefully we can translate it nicely to the human eye. We just need to think about the ways either through through small molecules or maybe even gene therapy to bring this to human.

• 10:08Ira Flatow?

  And that's where you come full circle because you're a molecular biologist.

• 10:12Speaker 02

  Yes, this is how we work.

• 10:15Ira Flatow?

  Well, I'm glad you've shared that with us. Thank you for taking time to be with us today.

• 10:19Speaker 02

  Thank you. Thank you for asking those great questions and having me share your, my love.

• 10:27Ira Flatow?

  Dr. Dorota Skofranska Krawczyk, Associate Professor at the University of California, Irvine, who studies the mechanisms of aging.

• 10:40Ira Flatow?

  Coming up after the break, a different kind of eye. This one is the eye in the sky that's changing our understanding of the universe. Of course, I'm talking about the James Webb Space Telescope. Stick around.

• 10:55Speaker 00

  Science Friday is supported by PBS, presenting Going Wild. If you love learning about the natural world and meeting the scientists who help us understand it, be sure to check out the new season of Going Wild with Dr. Ray Wynn Grant. It's the chart-topping and Webby Award-winning podcast from the folks at Nature on PBS, now with a video companion series. In this season of Going Wild, host acclaimed wildlife ecologist Dr. Ray Wynn Grant heads out into the field to explore the animals, people, and stories that make nature worth saving. Stops include a hibernating black bear den in Arkansas and an underwater shipwreck site off the Florida coast. If you're looking for a place to start, check out the season's debut episode, where Ray joins beloved biologist and influencer Jordan King in the Florida Everglades to learn about

• 11:39Speaker 00

  his unlikely journey into science and how to study a wetland when it's not very, well, wet. So don't miss out. Follow Going Wild with Dr. Ray Wynn Grant on Apple Podcasts, Spotify, YouTube, or wherever you get your podcasts. Support for Science Friday comes from Science Sandbox, an initiative of the Simons Foundation.

• 12:03Flora Lichtman?

  Hey, it's Flora. Speaking of remarkable eyes, one of you dear listeners called us with questions about the biggest eye in the sky, the James Webb Space Telescope, and what kind of technology had to be invented to see farther back in time than ever before. And we live to serve. So here to see that we get some answers is the James Webb Space Telescope Project scientist, Dr. Macarena Garcia Marine. Welcome back, Macarena, and thanks for doing this. Thank you so much for having me, Flora. It's lovely to be back. Let me start by introducing you to our listener who called with this question.

• 12:39Speaker 04

  Hi, my name is Leon, and I'm from Kennewick, Washington.

• 12:43Flora Lichtman?

  Leon's 18 years old.

• 12:45Speaker 04

  So I'm just finishing up high school, but I'm taking classes at the local community college. And then I'll be going to university after I serve a mission for two years for my church.

• 12:57Flora Lichtman?

  And Leon's into space, and he's into James Webb, and he heard this thing about the James Webb Space Telescope that caught his ear.

• 13:05Speaker 04

  I heard once that the gold-plated mirrors on the James Webb Space Telescope have remarkably small imperfections. The analogy I heard was that if it were the size of the United States, the highest bump would be the size of a baseball.

• 13:19Flora Lichtman?

  Macarena, that seems wild to me. Is that true?

• 13:24Speaker 05

  It's actually not quite true because it is better than a baseball.

• 13:31Flora Lichtman?

  Really?

• 13:32Speaker 05

  Yeah, really. And I think Liam is referring to those tiny bumps, imperfections that's, you know, they are there and you cannot do anything about them. And those would be, give or take a 30% smaller than a baseball if a mirror would be the size of the United States.

• 13:49Flora Lichtman?

  We're in golf ball territory.

• 13:50Speaker 05

  Oh, yeah.

• 13:53Flora Lichtman?

  That's amazing. I mean, why do you need such a perfectly flat mirror?

• 13:58Speaker 05

  Well, because when you want to observe the very first galaxies that were created in the universe, or when you want to observe nearby objects, but with a really exquisite detail, you do need that size and you do need that perfection. Otherwise, things will be blurry.

• 14:14Flora Lichtman?

  For sharpness, for acuity.

• 14:16Speaker 05

  It is sharpness and acuity.

• 14:17Flora Lichtman?

  Okay, let's get to Liam's other question. Here's what he wants to know.

• 14:22Speaker 04

  My question is what the biggest hurdles were in terms of what technology they needed to develop and how they got past those and how they figured out solutions to their most complex problems.

• 14:36Flora Lichtman?

  What were the biggest challenges? Are there things that still haunt you?

• 14:40Speaker 05

  No, because it's going so well.

• 14:44Speaker 05

  Well, because he's interested on the mirrors. There were many technologies developed. The manufacturing of the mirrors was fresh and new, but specifically the polishing of the mirrors require new technologies and the measurement of those imperfections require development of new techniques. And this is because when you build one of these telescopes, they are a one-off. So you really have to do new things to make it as perfect as possible.

• 15:14Flora Lichtman?

  So what did you have to develop to make sure it was as flat as it was?

• 15:19Speaker 05

  There is a lot when it comes to building this telescope of...

• 15:24Speaker 05

  Processes and engineering. So in this case would be first of all, select the right material. Make sure the material is gonna behave well when it gets really, really cold. Because it's in a space and it would be very cold. But also make sure that the polishing, they are made out of beryllium metal and that they had to be polished to perfection. So for instance, there was a development of a technique to measure those tiny bumps, to measure them very precisely, to make sure that it was as flat as possible. And today, that technique or part of that technique, it's used to diagnose and to really measure surfaces of eyes to make sure that they can be perhaps be used by optometrists or by doctors to do surgeries.

• 16:09Flora Lichtman?

  Oh, to see if your if your eye has any imperfections on it.

• 16:13Speaker 05

  Right, just to measure the surface of the eye. So it is actually used in medicine, which is one of those, you know, spinoffs, as NASA calls them, technology you develop for a purpose and then it trickles down into society.

• 16:26Flora Lichtman?

  Wow, that's really cool. That's exactly what Leon was asking about.

• 16:30Speaker 05

  Yeah, that he has really good questions.

• 16:34Flora Lichtman?

  You know, before I hung up, I asked Leon why he was interested in space. And and his answer caught me off guard.

• 16:42Speaker 04

  This might be an unusual answer, but I'm a deeply religious person. And science is kind of, uh, for me, has strengthened my relationship with God. And I feel like helps me to understand the Creator a little bit better. And so it just makes me feel, um, I guess, hope and and joy for something greater out there than than us.

• 17:08Flora Lichtman?

  Macarena, I loved this sentiment and I wondered how it would hit you.

• 17:12Speaker 05

  That's a lovely, um, answer. I think when it comes to the universe and we we look at any of, you know, even the night sky or or any of, um, the telescope's results, you always wonder about the big questions. I think where do we come from? Where are we going? What is the origin of everything in this case? What is the origin of the universe in the big bang? So I think there is a An interplay that is very clear there.

• 17:42Flora Lichtman?

  Yeah, and there's awesomeness in both fields, right? And I mean that in the, you know, the true sense of the word, that there's awe.

• 17:51Speaker 05

  Yeah, there is absolute awe. And think of the big one, right? That particular moment, which is the creation of our universe. So we can study the universe afterwards, but it can also be addressed from a religious perspective as the moment of creation. So I think there's a lot to think about that.

• 18:15Flora Lichtman?

  Leon had one more thing to tell you, Macarena.

• 18:18Speaker 04

  What you've done is super awesome. And thank you for what you've done for science and exploring space.

• 18:26Speaker 05

  That's fantastic. And thank you to Leon. But this is, of course, the effort of thousands and thousands of people. It takes a village. And none of this, none of this happened by chance. These were very well planned and thought of, engineering the science and science objectives, and really teamwork that made it happen. But thank you. And it really was my day to hear that.

• 18:55Flora Lichtman?

  Thank you, Macarena. Thank you for joining us today.

• 18:57Speaker 05

  Thank you.

• 18:58Flora Lichtman?

  Dr. Macarena Garcia-Marine is a project scientist for JWST. And Leon, thank you for the wonderful question. This show is produced by Rasha Aridi. And if you have a question that you need an answer to, give us a ring, 8774 Sci-Fry. Catch you tomorrow. I'm Flora Lichtman.