Protect your eyes during the total solar eclipse

[00:00:00] Host Amber Smith: Upstate Medical University in Syracuse, New York invites you to be "The Informed Patient" with the podcast that features experts from Central New York's only academic medical center. I'm your host, Amber Smith. If the weather cooperates and the clouds stay away, Central, Northern and Western New Yorkers will be able to observe a total solar eclipse on Monday, April 8th. For help understanding how to avoid severe eye injury, I'm talking with Dr. Robert Fechtner, professor and chair of ophthalmology and visual sciences. Welcome back to "The Informed Patient," Dr. Fechtner.

[00:00:34] Robert Fechtner, MD: Thanks. It's great to be back here with you Amber.

[00:00:38] Host Amber Smith: A lot of people who live here and a lot of people who travel to Central or Western or Northern New York plan to watch the total eclipse, so what's important to know about how to do this safely?

[00:00:49] Robert Fechtner, MD: First of all, how lucky are we that the solar eclipse is coming to us, and we don't have to travel across the country to see this? I am so excited to see a total solar eclipse. It is truly a wonder of nature. In ancient times, it was a very frightening experience. And now the only thing that frightens me is the weather. So I'm hoping for a really clear, sunny day.

People will, and if they can, should, take the opportunity to go out and witness this. It is spectacular, and it is very easy to do it safely. So I'm glad we're talking today about how to safely experience this wonder of nature.

[00:01:33] Host Amber Smith: So is it safe to just look through binoculars, or a telescope?

[00:01:38] Robert Fechtner, MD: Amber, there's a great temptation to look up into the sky and look at the sun. And as all of us know, every once in a while you look up, you catch the sun, that's not dangerous. You know, an instant of sunlight in your eye is just part of every day.

The danger is that it's going to be so fascinating we're going to want to watch the whole thing, and you cannot do that with the naked eye. Even worse would be to try to do it with binoculars or telescope. And let me tell you why that is. And I'll go back to when I was a little kid and I had a magnifying glass. You can guess that I'm a professor, and I was always a science nerd, but on a bright, sunny day, we could take our magnifying glass and a piece of paper and burn a hole through the piece of paper with the magnifying glass. The magnifying glass is a lens.

Your eye works very similarly. There's a lens inside your eye, and its only purpose is to focus light on the retina. So that same sunlight that could burn a piece of paper when I was a kid can burn the retina if you are looking at it. If you use a telescope or binoculars, you amplify that concentration of sunlight. So absolutely, you have to avoid those unless it is a specially made optical device for viewing a solar eclipse.

[00:03:09] Host Amber Smith: So I'm guessing the camera in my cell phone also has a lens, so that's probably a no-no as well?

[00:03:16] Robert Fechtner, MD: Your cell phone will be very unhappy if you try to take pictures. And that is not a good idea, and trying to use the cell phone to look at it. Fortunately, your cell phone screen is not bright enough to injure your eye, but the sun is bright enough to injure your cell phone.

[00:03:33] Host Amber Smith: So we really kind of are left with the naked eye, but we need protection. Do sunglasses offer that?

[00:03:41] Robert Fechtner, MD: You can't use sunglasses. In fact, any lens that you're able to see through in daylight is not dark enough. I just went on Amazon last week and bought a hundred pairs of eclipse sunglasses. So plan early. You've got to get them. I don't think people will sell out, but you don't want to be looking for those a day or two in advance.

Regular sunglasses are filtering a little bit of daylight. You need a much, much darker, denser lens to be able to safely look at the sun.

[00:04:17] Host Amber Smith: Can you put those eclipse glasses over the binoculars?

[00:04:22] Robert Fechtner, MD: You know, it sounds like a clever idea to do that, but the binoculars concentrate the light further, and that's not considered a safe practice. And for somebody who is truly devoted to watching this eclipse, you can go online and you can buy binoculars that are so densely filtered that they are safe, but you have to make sure that they're coming from a reputable source. And if you look through something and you can see the light in your ceiling, then it is not dense enough. They really have to filter out a lot of light for you to be able to point it at the sun.

[00:05:02] Host Amber Smith: What if it's overcast on April 8th? Can you safely look at the eclipse through the clouds?

[00:05:08] Robert Fechtner, MD: The rays are still strong. They will be slightly filtered, but not enough that you should be looking directly at the sun. It's a dose response. So a somewhat filtered sun will take longer to burn the retina, but it will burn the retina. And you're going to watch the eclipse for 10 or 15 minutes.

[00:05:27] Host Amber Smith: So these eclipse glasses, do they need to be worn during the partial eclipse, as the moon moves in front of the sun?

[00:05:37] Robert Fechtner, MD: The recommendation is as long as it's a partial eclipse, you still have that very bright portion of the sun. And as an ophthalmologist, I've seen people who've had sun damage. There are people who have, for various reasons or mental illness, decided to stare at the sun, and they end up having a circular burn in their vision. If you test them, there's just a circle that's punched out. They can't see.

If you were looking at a partial eclipse, you wouldn't have a circle. You would have a semicircle or a crescent burn.

No, it is not safe to look at the sun anytime other than the totality when the entire sun is blocked out. And that's brief, but I expect it to be really dramatic.

[00:06:24] Host Amber Smith: Can you describe an alternative way to watch, without looking at the sun?

[00:06:29] Robert Fechtner, MD: Sure. I'll start out by saying now that you can buy cardboard eclipse sunglasses for a dollar or two,I hope most people will go that direction.

There's an optical trick you can do, which is called a pinhole projector. And if you took something as simple as a three by five file card, and you poke a hole in it, and a ballpoint pen tip is a good size to do that. Then you can turn your back to the sun, hold up that pinhole and put a piece of paper behind it, and it will project the circle of the sun on it. As the eclipse is projecting, you will see that circle start to shrink as the moon comes into view.

I love optics. I'm an ophthalmologist, so I'll have some of my friends around me, and even though we'll have the sunglasses, we're going to do that just because it's a fun science experiment. And there are instructions online how to make a pinhole eclipse viewer.

[00:07:34] Host Amber Smith: This is Upstate's "The Informed Patient" podcast. I'm your host, Amber Smith. I'm talking about how to safely view the total solar eclipse with Upstate's chair of ophthalmology, Dr. Robert Fechtner. The total solar eclipse crosses North America on Monday, April 8th, from Mexico through the United States and into Canada. The partial eclipse starts at 2:09 in Syracuse, with the total eclipse lasting one minute, 24 seconds, starting at 3:24. The partial eclipse then ends at 4:35.

So you mentioned that you've seen patients that you've cared for that have looked directly at the sun and have suffered, is this lasting damage?

[00:08:16] Robert Fechtner, MD: Sadly, Amber when you burn the retina, and that's the inside part of the eye that senses light, there are no longer rods and cones there. And that part of the retina won't be able to see light anymore. It is truly a punched out small circle, but because people stare at the sun, it's a punched out circle right in the center of their vision.

It can make it nearly impossible to read. And I would roughly equate it to having something like macular degeneration. It takes away your central vision. It is not worth taking the risk you have to get a proper pair of solar eclipse glasses. Or, if for some reason there are none available, do the pinhole projector we just talked about. The American Astronomical Association has some descriptions online. There are other reliable sites online, and don't take the risk of burning the retina. Do not look directly at the sun, no matter how attractive this event is going to be, unless you're wearing proper protection.

[00:09:20] Host Amber Smith: If someone does look at the sun, does it hurt? Will they feel that they are hurting their eyes?

[00:09:25] Robert Fechtner, MD: The body is interesting, the way it protects it. We have pain receptors all over our skin. There's no need for pain receptors inside the eye in the retina, and there are no pain receptors inside the eye and retina. So it would just be a right dazzling view, but it would have lifelong consequences.

So if you're looking at something, and it seems really bright, it's a good time to look away. I'll draw a little parallel. Many of us have had a photograph with a flash camera, and you notice right after the flash, you can't see where that flash was. Imagine that being a permanent blind spot. That's what happens if you look at the sun for too long.

[00:10:15] Host Amber Smith: If someone realizes that they've done that, or maybe their child has done that, is there any emergency care that they can render, or do they need to do anything right then?

[00:10:26] Robert Fechtner, MD: This is where prevention is the only answer. We do not yet have the ability to transplant or restore burned nerve cells. So for your children, supervise them. I have a hundred sunglasses here. If you're in the neighborhood, stop by. I'll give you a pair. And we are handing them out to all of our staff and patients who are in the office. We'll go out the back door and we are going to take a break for the solar eclipse.

[00:10:58] Host Amber Smith: Now, for the eclipse glasses, is there a way to tell whether you're getting good quality eclipse glasses?

[00:11:06] Robert Fechtner, MD: Well, there is a standard for them, and I won't give you the numbers because nobody's going to take a look and see that it's ISO (International Organization for Standardization) 1 2 3 1 2 - 2. I just gave you the numbers. But there is a standard for them. The ones online are probably reliable. And I expect we're going to see them in an awful lot of stores along the path of the total eclipse. But do look and make sure that they are certified as being solar eclipse safe. Or it will say "filters for direct observation of the sun."

And a quick test you can do is if you put them on, the only thing you should be able to see through them is the sun. You won't see other people, you won't see a flashlight. They are a very dark, dark glass to let just enough light through for you to be able to safely watch the eclipse.

[00:12:00] Host Amber Smith: So they're not at all like regular sunglasses.

[00:12:02] Robert Fechtner, MD: They are not like sunglasses. Save your sunglasses for going out on a bright, sunny day. You need these special glasses. And fortunately now they are so inexpensive, I think most people will find it quite affordable. Buy some. Buy some for friends. Hand them out to anybody standing next to you who doesn't have them. Be generous.

There are also binoculars that have these filters built in. So if you are truly devoted, you can find those. But don't try to put on the eclipse sunglasses and then look through binoculars. The binoculars concentrate too much sunlight and will make it too bright for the eclipse glasses to do their job.

[00:12:47] Host Amber Smith: Well, this has been really important advice, and I thank you so much for making time to tell us about it, Dr. Fechtner.

[00:12:53] Robert Fechtner, MD: Amber, I'm so glad to be here. I hope everybody has a bright sunny day on April 8th. Go see the eclipse, and be safe.

[00:13:04] Host Amber Smith: My guest has been Dr. Robert Fechtner, professor and chair of ophthalmology at Upstate. "The Informed Patient" is a podcast covering health, science and medicine, brought to you by Upstate Medical University in Syracuse, New York, and produced by Jim Howe. Find our archive of previous episodes at upstate.edu/informed. If you enjoyed this episode, please tell a friend to listen too, and you can rate and review "The Informed Patient" podcast on Spotify, Apple Podcasts, YouTube, or wherever you tune in. This is your host, Amber Smith, thanking you for listening.