Protect your eyes during the total solar eclipse

[00:00:00] Host Amber Smith: Upstate Medical University in Syracuse, 纽约邀请您成为“知情患者”，收听播客，介绍来自纽约中部唯一学术医疗中心的专家. I'm your host, Amber Smith. If the weather cooperates and the clouds stay away, Central, 周一，纽约推荐最近最火的赌博软件和西部的居民将能够观测到日全食, 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: 许多住在这里的人和许多去纽约中部、西部或推荐最近最火的赌博软件旅行的人都计划观看这次日全食, 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.

人们会，如果可以的话，应该抓住机会走出去见证这一切. It is spectacular, and it is very easy to do it safely. 所以我很高兴我们今天讨论的是如何安全地体验这一自然奇观.

[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. 我们都知道，每隔一段时间你抬头一看，就会看到太阳，这并不危险. You know, an instant of sunlight in your eye is just part of every day.

危险之处在于，它太迷人了，我们会想看完整部电影, 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, 我们可以用放大镜和一张纸，用放大镜在纸上烧一个洞. The magnifying glass is a lens.

Your eye works very similarly. 你的眼睛里有一个晶状体，它的唯一作用是将光线聚焦在视网膜上. 所以，当我还是个孩子的时候，同样的阳光可以燃烧一张纸，如果你看着它，也可以燃烧视网膜. 如果你使用望远镜或双筒望远镜，你就放大了太阳光的集中. So absolutely, 你必须避免这些，除非它是一个特殊的光学设备来观察日食.

[00:03:09] Host Amber Smith: 我猜我手机里的相机也有镜头，所以这可能也是禁忌?

[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. 事实上，任何你能在白天看到的镜片都不够暗. 我上周刚在亚马逊上买了一百副日食太阳镜. 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, 你可以在网上买到双筒望远镜，它们经过密集的过滤，很安全, 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. 它们必须过滤掉大量的光，这样你才能把它指向太阳.

[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. 它们会被轻微过滤，但不足以让你直视太阳. It's a dose response. 所以经过过滤的阳光会花更长的时间来灼伤视网膜，但它会灼伤视网膜. 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, 除了整个太阳都被遮住的时候，任何时候看太阳都是不安全的. 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. 我首先要说的是，现在你可以花一两美元买到硬纸板的日食太阳镜,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. 随着月食的投射，你会看到月亮进入视野时，圆圈开始缩小.

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. 我说的是如何和上州眼科主任一起安全地观看日全食, 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.

你提到过你照顾过的病人因为直视太阳而感到痛苦, 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. 你不值得冒险去买一副合适的日食眼镜. 或者，如果由于某种原因没有可用的，做针孔投影仪我们刚刚谈到. The American Astronomical Association has some descriptions online. 网上还有其他可靠的网站，不要冒灼伤视网膜的风险. 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. 所以这只是一个令人眼花缭乱的景象，但它会产生终生的影响.

所以，如果你正在看某样东西，它看起来非常明亮，那就是把目光移开的好时机. 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. 我们把它们分发给办公室里的所有员工和病人. 我们从后门出去，在日食的时候休息一下.

[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, 我就不告诉你具体数字了，因为没人会去看，会发现它是ISO(国际标准化组织)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. 我希望我们能在日全食沿途的很多商店里看到它们. 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, 深色的玻璃可以让足够的光线穿过，这样你就可以安全地观看日食.

[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. 幸运的是，现在它们很便宜，我想大多数人会觉得它很实惠. 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. 但不要试图戴上日食太阳镜，然后用双筒望远镜观察. 双筒望远镜聚集了太多的阳光，会使它太亮，使日食眼镜无法发挥作用.

[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 1e1v.com/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.