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The Dose Transcript for April 4, 2024

Host: Brian Goldman

BRIAN GOLDMAN: Hi, I'm Dr. Brian Goldman. Welcome to The Dose. Well, there's a near once in a lifetime solar eclipse on the horizon in many parts of North America, and many of you are excited and plan on watching. Of course, viewing a solar eclipse needs special protection. So this week, we are asking, how can I watch a total eclipse or close to total eclipse of the sun and keep my eyes safe? Hi, Yi Ning. Welcome to The Dose.

YI NING STRUBE: Hi. Thank you for inviting me.

BRIAN GOLDMAN: Are you planning on watching the eclipse?

YI NING STRUBE: I am planning on watching the eclipse. I unfortunately will not be in Kingston, where there is quite a long totality. I've been invited to be in a meeting in Austin, Texas, where we will have totality, but only for about a minute.

BRIAN GOLDMAN: And of course, it only takes a minute to cause damage to your eye if you're watching unattended. So that's why we wanted to get you on the show. But before we begin, can you please give us a hi, my name is? Tell us what you do and where you do it.

YI NING STRUBE: Hi, my name is Dr. Yi Ning Strube. I'm a pediatric ophthalmologist, and I also see adult strabismus patients at Queen's University and Kingston Health Sciences Centre. And I'm director of that service, and also the current president of our Canadian Association for Pediatric Ophthalmology and Strabismus.

BRIAN GOLDMAN: What do we know from past experience? How much has the eyesight of some people been damaged by gazing at a solar eclipse without proper protection?

YI NING STRUBE: There have been two more recent total eclipses. Once was in 1999 in the United Kingdom, and more recently in North America, 2017, The Great American Eclipse. So from those studies, we’re able to see what potential damage has occurred. Is it permanent? Is it temporary? And although some of the blurriness and immediate symptoms can be transient, the damage to the retina, the back of the eye, is usually permanent and creates little, what we call scotomas, missing areas of the central part of your vision, and it can occur with very little exposure to the eclipse.

BRIAN GOLDMAN: So it's the central part of the retina that is most likely to get damaged. How important is the central part of the retina?

YI NING STRUBE: The central part of the retina, we call that the macula, the phovia. It's what we use for vision. So everything else is peripheral vision. So when you're looking, you know, you're looking straight ahead, but you see things coming at you from left or right. But our central vision is what we use every waking moment for reading, for driving, for everything. As you may have heard and what we're trying to emphasize from a public health perspective is that we normally don't look at the bright sun because normally, there's a blink reflex. Or if we do glance at the sun quickly, we look away. However, with the eclipse, you know, you're staring with wide eyes open. And it's just before totality and just after, when there's only a small sliver of light that doesn't cause that aversion to bright light, that still has as bright a light as possible, that can then cause that photo oxidative stress to the back of the eye and cause that permanent damage. So it's really just before and just after where you may have the false sense of security that that light's not damaging your eye because it's not as bright as you're accustomed to. And especially for younger children or anyone who may not have the knowledge or the ability to look away during that time or have proper glasses on, that's really the dangerous time point.

BRIAN GOLDMAN: What part of the sun's rays, what part of the spectrum causes the damage?

YI NING STRUBE: It's mostly the UV light. And so the special eclipse glasses lock out 99% of the UV light as well as the infrared light. You know, you can get what's called solar retinopathy not just with looking at the sun. So that's been reported with things like arc welding. Even, you know, operating microscopes if looked at the light too long, that can cause some damage. But it's a combination of the UV and infrared light.

BRIAN GOLDMAN: So obviously, we don't want people to look directly at a solar eclipse. But if you were to make that mistake of looking directly at it, what are some of the symptoms you might notice?

YI NING STRUBE: So the reported symptoms of looking at a solar eclipse include vague symptoms like sensitivity to light, some blurry vision, sometimes headaches. And as I mentioned just a few minutes ago, these missing areas. So in your central vision, little areas where it looks like it's a bit blackened or, you know, shadowed punched out areas. Patients have also mentioned what we call metamorphopsia. So things look wavy where you know that they should be straight or even variations in the colour. And that's, again, all damage to the photoreceptors in the macula.

BRIAN GOLDMAN: Would you actually notice blind spots, what you called scotoma, right away, or is that something that it would take some, you know, hours or days for you to begin to notice?

YI NING STRUBE: Patients have mentioned these symptoms within the, you know, the first few hours of looking at the sun.

BRIAN GOLDMAN: How long does it take to notice symptoms, to actually have damage to your retina?

YI NING STRUBE: Going from these reports, some of them a little bit older, seeing the changes in what we call the macula have been reported even, you know, the next day. Whether they were there immediately after, usually, you know, there's time before the patient is actually seen in the clinic. But using a specialized test called optical coherence tomography, basically looking at the very fine detailed layers of the back of the macula, we can show changes very early on. And in some cases, those changes resolve, but it takes months. And in a lot of those patients who have permanent changes, what they see, you know, on day one of presentation, those cellular changes in the retina are still there months out.

BRIAN GOLDMAN: And how many seconds or minutes of gazing at a solar eclipse does it take to start the process of damage?

YI NING STRUBE: When we looked at some of the previous reports of patients looking at the solar eclipse, it's historical recall. How long were you looking? But it's been seconds usually, as I said, it's just before totality, but it's not oh, I was looking at it for 10 minutes. I was gazing at the sun for a long period of time. So that's the concerning thing that, you know, even looking for 30 seconds without blinking, without looking away, could be damaging.

BRIAN GOLDMAN: You know, I want to bring up a point of clarification, because we have some very astute subscribers who listen to every word in these podcasts, and hearing you, they might get the impression that you don't know because you're not treating patients who have been exposed to a total eclipse of the sun. But there's a really important ethical point here. You can't do a study, a prospective study in which you're going to have, you know, one part of the population in your, you know, your study group exposed to total eclipse of the sun and another one who isn't, because that would be unethical. You can't do that. You can only gather case reports after the fact, am I right?

YI NING STRUBE: Yeah, 100%. That study will never happen where we purposefully shine dangerous light rays into a patient and then immediately look at the retina. So it's based on historical looking at patients who present with complaints, subjective complaints, and then looking and seeing, you know, objectively, where's the damage? But as I said, it's not just with solar eclipses, which occur less frequently, but with arc welding and other, you know, other sources are bright lights. Again, ethically, we can't test that. The other important fact is there is no treatment. If that message is also out there, perhaps patients don't present as early. But you're right. I can't tell you for certain, does the damage occur immediately and would you see it on testing? It probably does, but I can't tell you 100% for sure.

BRIAN GOLDMAN: So you're saying, though, that it's an ophthalmological, it's an eye emergency. And people, you know, if they think they've been damaged, if they think they're having, if they're having visual distortions, headaches, symptoms, loss of vision, they should seek immediate attention by going, I guess, to an emergency department. What can ophthalmologists do? What can I specialists do for somebody who may have been damaged by a solar eclipse?

YI NING STRUBE: I guess I'd like to clarify that. I would say it's an emergency in the sense that something has happened immediately to change your vision. And I would recommend that if a patient, for whatever reason, experiences a change in their vision, they should seek help. Ideally, if they have an eye care provider, so an optometrist, or if for some reason, they have an ophthalmologist, seek care with them because they will have the information about that person's baseline vision. It's not an emergency in the sense that the sooner you are seen, you will get treatment, because unfortunately, there is no treatment for this. From a practical standpoint, rushing to the emerge, especially in the Kingston area, there's predictions of anywhere between 70,000 to half a million people flooding to our area with potentially other, you know, non-solar eclipse related health problems happening at that time, the knee jerk reaction shouldn't be to go to emergency. I think this can wait for 12 hours, till the next day, and to see your regular eye care provider.

BRIAN GOLDMAN: But from what you're saying, there are no treatments. That's the reason why there's no point in rushing to an emergency department.

YI NING STRUBE: Exactly. You know, there's been investigations for how can we treat this? Nothing has panned through. There's no treatment. So that is why there's so many ophthalmologists and optometrists trying to spread the prevention is key word, and it's relatively straightforward prevention for those of us who can plan ahead. So hopefully, the number of people who do get solar retinopathy is almost zero. Zero would be ideal, obviously.

BRIAN GOLDMAN: So obviously, we want to take steps. We want to warn the public to protect themselves. What sorts of protective eyewear will be effective?

YI NING STRUBE: Regular sunglasses, regular prescription glasses, regular safety glasses you may wear for other reasons, none of those will protect from the solar eclipse rays. And I'm sure most of the listeners have heard about these solar eclipse glasses. They have to have this special certification. So it's ISO 12312-2. But even more than just that number is to ensure you've received glasses from a reputable source. So discouraging getting them online from non-reputable sources. If you go to the NASA website, they have good resources about where to get the glasses in a lot of the cities. I can only speak to Kingston, but the city of Kingston is selling them. Queen's University is supplying them to all students and staff. Our hospital’s supplying them to all employees. So hopefully, in most communities, it's relatively easy to get a hold of these glasses. But it's really important that you don't use a pair that falsely advertised. So unfortunately, there are counterfeit eclipse glasses. What we've been told, you know, when you wear these glasses, they're completely… it blacks out everything. So if you wear them carefully in the house beforehand, and if you can see normal house lights or any light through them, they are not going to protect you. And it's also very important that the glasses aren't bent or crumpled or scratched, because again, that will allow some of those harmful rays to enter your eye.

BRIAN GOLDMAN: And if you can't find appropriate eyewear, can you look through a pinhole?

YI NING STRUBE: There's lots of different options, and I think it's a wonderful educational event. I know the schools locally, and I'm sure all around the viewing areas, are talking about how to experience this. It's going to be broadcast live I believe on the NASA website, so you don't have to be looking directly at the solar eclipse, I think, in order to experience the wonder of this and to learn about the science. And again, our Queen's ophthalmology website has some links. The physics department here at Queen's has some great educational resources about the pinhole and other ways to observe. And there's other apps that you can experience the solar eclipse for our low vision patients as well.

BRIAN GOLDMAN: Can you talk about the prognosis? What percentage who suffer some eye damage will recover, and what percentage will have permanent damage based on the case reports that we have?

YI NING STRUBE: Case reports showed that the symptoms like the headaches, the sensitivity to light, blurred vision, that usually resolves. However, the small scotomas, those usually stay. And again, I don't have all the numbers in front of me, but there was one study from Utah from the 2017 American Eclipse. They had six of 27 patients with visual changes, and they ended up having those remaining scotoma that we could document on on that special testing the OCT. So the longer the duration looking at the eclipse, the more likely the scotomas would last. Interestingly, the study from the U.K., in the areas where there was not complete totality but just off of totality, those were the patients who were or the population that was more affected, again, because of that false sense of security. I think if there's total blackout and you take the glasses off, that's going to be safe. And it's probably more obvious than when there's a little sliver of light and you may be so mesmerized or fascinated by what you're seeing and forget the importance of the safety glasses.

BRIAN GOLDMAN: Last question I want to ask you. You're a pediatric ophthalmologist, which means that you treat children. I know you also treat adults, but you treat children. I think there's a special impetus to prevent kids from looking up at the light. What should parents do to protect their kids?

YI NING STRUBE: It's tricky. Anyone who has children, worked with children, helped taking care of them, know that there's no set age where a child is safe to look at an eclipse with the glasses on or not. I'm telling families, my patients and the public, make a judgement. In an ideal situation, if you can have one on one, you know, responsible adults with a child, that would be best. Some kids have aversion to having things on their face. I would try, you know, practice with the glasses carefully before the day of the eclipse so they're used to what's going to be on their face. And if they don't like it on the non-eclipse day, choose some of the alternative ways to enjoy the event. Mostly across the viewing areas in Ontario, kids will be home because it's been a PA day from school. So it's really the onus is on the parents to make sure their kids are safe. You know, talk to the kids about the dangers of looking at the sun. But at the end of the day, you know, I have young kids of my own, and sometimes they listen, sometimes they don't. So I would just tell parents, you know, they know their kids best, and know that it only takes a, you know, really a few seconds for there to be damage. And kids really won't understand that damage until after the fact. And so one on one care with an adult and a child makes sure that for everyone, as I said, they’re blackout glasses. So you are putting these on without moving. There's no running around with the glasses, no moving. And again, when you put the glasses on, look down. You know, maybe tell kids, look down at your feet away from the sun, put the glasses on, then you can look up at the eclipse. And then when you're taking them off, do the reverse. So look away. So always looking away from the sun when you're putting them on and off, that'll prevent any type of damage. And the pinhole, watching it on your computer or on the TV, that might be the safest option. I would say, you know, for young elementary children, of course, there'll be a range. I would on the side of caution.

BRIAN GOLDMAN: And in addition to erring on the side of caution, maybe promote how exciting it is to observe the eclipse from the safety of the NASA website or websites in Kingston.

YI NING STRUBE: I think so. I wouldn't want the message to be ignore this event. It's like everyone's saying, a once in a lifetime event. And it's amazing science and hopefully will excite some children to go into astrophysics or whatever other fields are involved in the research with the eclipse. So there's so much interesting things to be learnt online. I don't want that message to be that we ignore it, but just to also practically speaking. You know, I will be out of town. My husband will be with the three boys. And the logistics of him making sure all three take their glasses off at the exact same time and put them all back on at the exact same time is challenging, even though we know all about the risks.

BRIAN GOLDMAN: The eclipse may be a once in a lifetime event, but we only have a pair of eyes, and they're meant to last our lifetimes as well. Thank you for being on The Dose.

YI NING STRUBE: Thank you so much.

BRIAN GOLDMAN: Dr. Yi Ning Strube is an associate professor in ophthalmology at Queen's University, the director of pediatric ophthalmology with Kingston Health Sciences Centre, and the current president of the Canadian Association of Pediatric Ophthalmology and Strabismus. Here's your dose of smart advice. Eclipse retinopathy is damage that occurs to the central part of the retina as a result of gazing at a solar eclipse. It can also occur by gazing at the non-eclipse sun, except the thing about looking at a solar eclipse is that you don't blink or otherwise feel the physical need to look away. The damage can occur with just a few seconds of gazing at an eclipse. The symptoms include blurred vision, eye pain and patchy blind spots in the centre of your sight, causing difficulty with reading and distance vision. Most people affected have some improvement in vision and symptoms in the first three to six months after gazing at the eclipse, but vision changes that persist for six months following the injury are likely to be permanent. Since there's no effective treatment for the damage, you must protect your eyes. If you want to look directly at the eclipse, use safe ISO approved solar viewing glasses that filter out harmful sunlight. Make sure that the glasses are not torn, scratched, or otherwise damaged before use. Do not look at the eclipse through a camera lens, telescope, binoculars or any other optical device while wearing eclipse glasses. That's because optical lenses concentrate sun rays, which then may burn through the filters contained in safe viewing glasses and cause serious eye injury. This is very important. You must supervise your kids during the eclipse. Make sure your kids wear solar viewing glasses and that they look away from the eclipse while donning and doffing the glasses. If you experience any symptoms of eye damage after accidentally looking directly at the sun, see your eye care provider. If you have topics you'd like discussed or questions answered, our email address is thedose@cbc.ca. If you liked this episode, please give us a rating and review wherever you listen. This edition of The Dose was produced by Samir Chhabra. Our senior producer is Colleen Ross. The Dose wants you to be better informed about your health. If you're looking for medical advice, see your health care provider. I'm Dr. Brian Goldman. Until your next dose.

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How can I watch a solar eclipse and keep my eyes safe? - Transcript

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