Mount Sinai researchers used state-of-the-art imaging to closely examine a patient’s retina after the solar eclipse of August 2017 burned a crescent shape into her eye.
The tricky thing about a partial solar eclipse is that if you look at it directly, you won’t feel any immediate pain. But the sun’s energy can still permanently damage your retina—and your vision.
In this Q&A, Avnish Deobhakta, MD, Associate Professor of Ophthalmology at the New York Eye and Ear Infirmary of Mount Sinai, explains how to safely look at a solar eclipse and the potential harm that can occur if you do not follow basic precautions for viewing this spectacle, which will take place Monday, April 8.
Avnish Deobhakta, MD
Why should I avoid looking at a solar eclipse? What damage can it do to the eye?
The solar eclipse is a very, very dangerous event for your eyes. Light beams from the sky carry a lot of energy that can be transmitted into the retina and damage it. Usually, the sun is very bright and it’s almost impossible to look directly at it without discomfort. But during a solar eclipse, you can look at the sun for a long period of time and be fooled into thinking that it’s safe because it doesn’t hurt. This is because most of the sun’s rays are blocked off by the eclipse. But the sun’s rays that you see during a partial eclipse are the most damaging to the eye. It’s almost like you’re getting a disproportionate helping of the most energetic and damaging rays because all of the other rays are blocked and the ones that make it through are not so bright that they force you to look away.
What can happen if I take a quick peek?
Even a very quick look at a solar eclipse can burn your retina. During the last solar eclipse, in 2017, one of my patients looked at the eclipse and sustained damage to her retina. She thought she was using protective glasses—but they weren’t the right type. She still has a blank section, a visual blind spot, in the center of her visual field. I used groundbreaking technology to take a close look at the damage to her eye. The damage was in the exact shape as the moon—a crescent shape. We were one of the few sites that had that prototype machine and could take that photo. It may not help the patient, but it gave us new information about the damage caused by exposure to the sun’s rays. Other people have been known to have visual distortions in part of their visual field. Even with a total solar eclipse, there will always be a moment when the sun re-emerges, and some of those rays can damage the retina.
Is the damage permanent?
Yes. We cannot fix it. At the New York Eye and Ear Infirmary of Mount Sinai, we have the technology to take an image and see the part of the retina that is damaged, but there is nothing a doctor can do to treat it. The damage doesn’t go away. Even decades later, your vision will still be impaired.
Can I look using a mirror?
No. Mirrors reflect the damaging sun rays. Looking in a mirror is the equivalent of looking directly at the solar eclipse–it’s not safe.
What about special sunglasses? Are those safe?
It’s fine to use approved sunglasses that have the right filters. However, you have to make absolutely sure that you have those filters, and you need to obtain them from a reputable vendor. If you are not sure of either of those things, then you should not look at the eclipse, and instead look at a projection of the rays. Most of the people I’ve seen whose eyes were damaged by looking at a solar eclipse thought they were wearing the right glasses. And if you think you’re protected, you’re going to look longer, which increases the chances—and the extent—of damage. (Click here to learn more about safe viewing on the JAMA Patient Page created by the Journal of the American Medical Association.)
How about using a camera, like the one on my phone?
Generally speaking, if you look through your phone camera, you’re looking at an image rendered through the camera. You’re not actually looking directly at the sun, which means, theoretically, that it is safe. What worries me is not the phone camera—it’s that when people hold the camera up toward the sun, they might look around it for even just a brief period of time and can end up with a damaged retina. Think about a concert, when people have their phones out and are recording the concert, but they’re also looking around and watching the band on the stage. That’s not safe during a solar eclipse.
Is there a safe way to look at a solar eclipse?
Pinhole cameras are safe. They reflect light off an object and onto a surface such as a cardboard box or a wall. That way you’re not looking at the rays themselves, you’re looking at a projection of what the rays look like. You can watch a pinhole camera image as long as you’d like; you can even watch the entire solar eclipse reproduced on a pinhole camera and it’s perfectly safe. (Click here to get instructions on how to make your own pinhole camera.)
What if I’m outside during a solar eclipse but I don’t look up?
I don’t want anyone to think if they’re just in the presence of a solar eclipse they’re going to go blind. It’s okay to be outside during a solar eclipse, just be very careful. Be very mindful not to look directly at the sun in any way–and certainly not on purpose. The problem is that if you don’t know what’s going on and the sky looks different all of a sudden, your first instinct is to look up at the sun. The first instinct of all humankind is to look up. But that instinct can be dangerous during a solar eclipse.