Total safety of a solar eclipse: How to watch it without hurting your eyes

Young woman She visited New York Eye and Ear Hospital's Mount Sinai shortly after the solar eclipse on August 21, 2017. She told Dr. Avnish Deubakta, an ophthalmologist, that she had a black area in her vision, which she then drew in a crescent shape. On a piece of paper.

When Dr. Deopakta examined her eyes, he was amazed. He saw a burn on her retina that was exactly the same shape. “It was almost like a brand,” he said.

I've looked at the sun during the eclipse without any protection. The burn was an image of the sun's corona, its outer edge resembling a halo.

With each eclipse, ophthalmologists see patients who have looked at the sun and then complain that their vision is distorted: they see tiny black spots, their eyes water and are sensitive to light. Usually, symptoms disappear, although it may take several weeks to a year.

But the woman's retinal burns, which Dr. Deubakta and colleagues described in the medical case report, did not heal. Her retinas were permanently scarred, a sign of the seriousness of injuries that can follow looking at an eclipse without taking proper precautions.

As the April eclipse approaches, ophthalmologists advise people to be careful and not assume that even brief glances at the sun are safe. They say the damage can be done in less than a minute.

David Calkins, director of the Vanderbilt Center for Vision Research and vice president of the Vanderbilt Eye Institute in Nashville, said: Most at risk From retinal injury, perhaps because the lens of their eyes is clearer than the lens of older people. They may also be more reckless, he said.

But age does not guarantee safe viewing of the eclipse.

study Description of 20 people 15- to 82-year-olds in England who complained of symptoms such as black spots in their vision or blurry vision after the 1999 eclipse. Four of them said they used eclipse glasses; Someone said she used sunglasses. The rest was seen with the naked eye.

Five of them had obvious retinal damage. All but four of the 20 were better after seven months.

Not everyone is so lucky. study published Last year four young Irish women participated I looked at the sun During a religious gathering In October 2009. The women, who did not know each other, sought medical care within a few days of looking at the sun. They complained of blind spots in the center of their vision and said that objects appeared distorted and blurred.

Researchers from Galway University Hospital followed the women for an average of more than five years. One of them was followed for 11 years.

Years later, researchers reported that all of the women still had blind spots.

For Dr. Deubakta, the situation with women in 2017 is a cautionary tale.

While she was wearing goggles during part of her viewing of the eclipse, she initially looked at it several times for about six seconds at a time without protection.

I felt fine for four hours. Then her symptoms appeared: blurred vision, distorted shapes and colors, and that crescent-shaped black spot in the center of her vision in her left eye.

Most people view the eclipse through special eclipse glasses. Glasses often have a cardboard body with a special coating in the eye holes that filters out harmful rays.

Dr. Deubakta said he does not trust many of the eclipse glasses being sold, and feels it is not worth the risk. He prefers a Indirect way This involves using holes, such as in a colander, to cast the sun's shadow onto the ground.

Professional groups say many eclipse glasses are safe but urge caution when purchasing them. The American Astronomical Society reported this Potentially unsafe eclipse glasses The market was flooded before the 2017 eclipse.

To help people find eclipse glasses, the Astronomical Society Lists trusted sellers And distributors.

Legitimate eclipse glasses must meet specific international safety standards known as ISO 12312-2. The test requires a photometer that measures the amount of ultraviolet, visible, and infrared light that passes through the glasses.

But the ISO logo on glasses isn't necessarily a guarantee, the astronomical community warns, because dealers can — and some do — grab the ISO logo off the Internet and put it on their glasses.

Counterfeit companies also put the names of legitimate distributors on their products, said Rick Feinberg, project director of the Astronomical Society's Solar Eclipse Task Force. He added that this does not necessarily mean that they are unsafe. But this means that the seller, or the company that sold the products to him, is committing fraud.

Dr. Feinberg suggests purchasing directly from a seller listed by the Astronomical Society.

But if you're concerned about your glasses, he said, there's a way to know if they're effective. Look around the room wearing eclipse glasses. The glasses should be so dark that you can't see anything. Then go out and look at the sun wearing glasses. You're probably safe if you can see the sun through the lenses and “the image is comfortably sharp and bright,” he said.

Dr. Deubakta remains concerned. He says that he knows that he is very cautious, but he can only warn people about the upcoming eclipse.

He said: “Don’t look at him, whether you have glasses or not.” “I won't let my family members look at it. I'm a doctor. That's why I say what I say. I saw what happened.”