August 15, 2017

Don't look directly at the sun, and other eclipse-watching tips

By now you’re no doubt aware of the solar eclipse on Aug. 21, when the moon’s blocking of the sun will be visible over a large part of the United States.

It promises to be an impressive event, and the last time an eclipse of this scale occurred was in 1918. While it’s understandable that people want to be part of this historical event, it’s also critical to take some extra precautions.

Looking directly at the solar eclipse without protective eyewear can result in permanent eye damage and vision loss, said UW Health ophthalmologist Kimberly Stepien, MD, and it can take only a short time to occur.

“There is some thought that younger eyes are more susceptible, and it doesn’t take long for damage to occur,” she said. “Thermal energy from solar radiation can burn the macula of the retina which is the part of our eye we use for our central vision.”

She added that living with the damage can directly affect an individual’s ability to see for the rest of their lives. “It may result in a blank spot in the vision where, for instance, if one were to look at the word 'cat,' the 'a' may not be visible.”

The eclipse will take a few hours, but the full eclipse itself only lasts about 2 to 3 minutes. While campsites in what’s being called the "path of totality" have been booked by enthusiasts for months, most places in the U.S. will be able to witness some portion of the eclipse.

Here in Wisconsin, we’ll experience an 80 to 85 percent eclipse. Whether you are among those headed to an optimal viewing area, or you’re going to view from your own backyard, Dr. Stepien shares a few things to keep in mind:

How to view the eclipse safely

The safest way to view the eclipse is with a pin-hole projector (directions are available on the web, such as these from NASA’s Jet Propulsion Laboratory)

It is not safe to look directly at the eclipse using just sunglasses, films or homemade filters. Viewing the eclipse through cameras, telescopes or binoculars also is not safe.

“There is a thought that watching the eclipse through another set of lenses is safe, but that’s not true and we can’t emphasize enough that regular sunglasses are not sufficient,” Stepien said.

The eclipse can be viewed by using protective solar eclipse glasses. If you opt for these, be sure the glasses are ISO 12312-2 certified. Unfortunately, counterfeit glasses are out there, so before you purchase yours, make sure they are from a reputable seller with the manufacturer name on the inside part of the glasses. Also inspect the glasses to ensure they are not damaged - no scratches or bends – and not more than three years old.

“If children will be part of the solar eclipse viewing activity, close supervision is needed. It is critical to ensure the glasses remain properly on the face and be placed prior to looking up to view the eclipse,” said Dr. Stepien. “It’s easy – especially for young ones – for glasses to get bumped or shifted on the face, leaving the eyes unprotected.”

NASA will also be streaming the solar eclipse live through its website from multiple locations, which ultimately will be the safest way to view the eclipse. But if you do want to experience it firsthand, make sure you protect your eyes and do so safely.