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Published on August 18, 2017

Don’t let history blur your vision

Don’t let history blur your vision

For the first time in nearly a century, on Monday, August 21, everyone in the United States will be able to see either a full or partial eclipse. The path of totality begins at 9:05 a.m. in Oregon and bisects the country ending in South Carolina at 4:10 p.m.

Despite the historical nature of the eclipse, Hyannis ophthalmologist Eugene Ciccarelli, MD, will not be watching it himself and he recommends that other people refrain as well.

“I consider it risky to look directly at it under any circumstances with any glasses,” he said. “I would not do that. The best way to view it is to make one of those pinhole cameras with a box and set it up. As long as you are looking at it indirectly, that is fine. That’s not going to hurt anything.”

The term pinhole camera is confusing. It does not mean looking at the sun through a pinhole. Instead you project the sunlight through a hole onto a surface and look at the image on the surface indirectly.

Macular Damage

On Cape Cod, the eclipse will only be partial. The moon will cover 63.4 percent of the sun. The moon will be in the sun’s path beginning at 1:30 p.m. and continue for two hours and 30 minutes, with the peak at 2:49 p.m.

Even though a partial eclipse is less risky, Dr. Ciccarelli said that his best advice is to watch the eclipse by video. NASA is streaming the eclipse live on it’s website for those who want to watch the event safely.

“The problem is that if you’re going to look at it, you’re going to look at it directly with your macula, which is the very center part of the retina,” he said. “That’s the part that’s the most sensitive too, so all you need to do is get a nice little burn right smack in the macula and it can reduce your vision permanently.”

One of the other issues with viewing the eclipse is there are no pain receptors in the retina so there is nothing to warn you that you might be damaging your eyesight. The sliver of light coming from the sun during an eclipse may not be enough to scare you, but it is enough to burn you, he said.

“Ordinarily you can’t look directly at the sun because you’re getting such an intense radiation that your reflexes protect you,” he said. “But as the moon comes over the sun, it removes that protection. But nevertheless, in any particular spot that the sun focuses on the retina the intensity is the same as if you were looking directly at the sun. It is very intense. It’s like a laser.”

NASA Warnings

Dr. Ciccarelli knows that some people will assume the popular glasses that are being sold are safe. The problem is that many of them do not provide enough of a filter to shield your eyes properly and there is no way to test the viewers for safety at home.

With that in mind, the American Astronomical Society has created a list of reputable vendors of solar filters and viewers that meet ISO 12312-2 international safety standards. Most of the vendors have been sold out for weeks, but if you have already purchased filter glasses, it’s a good idea to check to see if yours are on the safe list.

NASA offers the following other warnings:

  • Always inspect your solar filter before use. If it is scratched or damaged in any way, discard it.
  • Always supervise children using solar filters.
  • Stand still and cover your eyes with the solar filter before looking at the sun and do not remove the filter until you are looking away from the sun.
  • Do not look at the partially eclipsed sun through an unfiltered camera, telescope, binoculars even if you have filter glasses on. The concentrated solar rays will damage the filter and cause serious injury.
  • If you are outside the path of totality, you must always use a safe solar filter to view the sun directly.
  • If you plan to use welder’s glasses, the only safe ones are those that are Shade 12 or higher, which is much darker than the typical filters that welders use. But be aware that even Shade 12 is considered too bright to ensure perfect safety.
  • Ordinary sunglasses do not protect your eyes. Do not use them to view an eclipse.

Even with all those safety precautions, Dr. Ciccarelli advised, “Just don’t look at it.”