Achi news desk-
Millions of people in parts of Eastern Canada and Atlantic Canada will be able to see the rare solar eclipse happening on April 8. But they should only look up if they have proper eye protection, experts say.
Why is viewing the eclipse more dangerous than viewing the sun on a normal day?
When people normally look up at the sun, the intense brightness triggers pain that causes them to look away quickly before it can cause damage, said Dr. Philip Hooper, president of the Canadian Ophthalmological Association.
But as the moon begins to block the sun in the period leading up to the total eclipse “there is significant light energy coming from the sun, but we don’t appreciate pain. And so you can look at it” long enough to damage the eye,” said Hooper, who is also an associate professor of ophthalmology at Western University in London, Ont.
How does staring at the sun damage our eyes?
When you look directly at the sun, intense visible light and infrared radiation are focused on the center of the retina at the back of the eye.
“Basically, it’s like taking a magnifying glass in the sun on a normal day and focusing that light on a piece of paper. It can get hot enough to burn the paper,” says Hooper.
The sun has the same effect, because your eye focuses that energy onto a small part of the retina.
“The temperature of the cells in that area can get high enough that the liquid in the cells boils and it permanently damages the cells,” he said.
This microscope image provided by New York Eye and Ear Hospital Mount Sinai shows damage to the retina of a person who viewed the 2017 eclipse without adequate protection. She complained of a black spot in her vision, and doctors discovered retinal damage that matched the shape of the eclipse. (Mount Sinai via AP)
Can I put my sunglasses on to watch the eclipse?
No. Sunglasses don’t provide protection, Hooper said.
What if I stay inside and watch through the window?
Again, no. Windows offers no protection.
Is it safe to watch through a phone camera?
No.
“Eclipse or not, you should not look at the sun directly with the naked eye, or with a camera or telescope, without a (certified) solar filter. This can lead to irreversible eye damage,” says an eclipse safety video posted on -line from the Canadian Space Agency.
Pointing your phone’s camera directly at the eclipse can have other consequences as well.
“Remember that your camera on your phone has lenses just like spectacles, and that light comes in from the sun as soon as you open the shutter,” says Elaina Hyde, director of the Allan I. Carswell Observatory in York University in Toronto.
“At least you could expect to damage your camera. You won’t be able to see anything, yet, because your phone can’t handle that light.”
How do I watch the eclipse safely?
You’ll need special glasses with filters designed for eclipse viewing, says the Canadian Space Agency’s website.
Those glasses must have side protection so light rays can’t get in, Hooper said.
They must also have certified lenses, he said.
The ISO 12312-2 certification should be printed on the glasses, which means that the glasses meet international safety standards.
When wearing the glasses, you should not be able to see anything unless you are staring at the sun.
“No matter how bright the light you’re exposed to in your indoor environment, if you shined a very bright light through them, you wouldn’t see anything. They’re pitch black. That’s how dark they are,” Hooper said.
The eclipse glasses should not be used if they are “scratched, punctured, torn, or otherwise damaged,” the American Astronomical Society says on its website, noting that people should inspect their glasses before use.
The association also says that children using the glasses during the eclipse must be supervised at all times.
Where can I get the ISO 12312-2 certified glasses?
Free eclipse viewing glasses are available in many libraries, cities and school districts across Canada, according to the Royal Astronomical Society of Canada website.
The American Astronomical Society has a list of companies and retailers in Canada and the United States that sell certified solar eclipse glasses on its website.
Some companies that sell them in Quebec are listed on the Eclipse Quebec website.
What about welding goggles?
Welding goggles come in a variety of shades, designated by number, according to the Canadian Center for Occupational Safety and Health’s website.
The minimum darkness required to view the eclipse safely is shade 13, Hooper said.
“That’s much darker than the welding glasses or goggles typically used by welders. And they’re not widely available,” he said.
If I don’t have the certified glasses, is there another option?
Another option for safe viewing is to make a projector so that you never look directly at the sun. It can be as basic as a piece of paper with a pinhole projecting sunlight onto the pavement, or a projector made out of a box.
The Canadian Space Agency website has simple instructions on how to make a projector using an empty cardboard box, a sheet of white paper, aluminum foil, a pin, tape and scissors.
For instructions, visit https://www.asc-csa.gc.ca/eng/youth-educators/activities/fun-experiments/eclipse-projector.asp
-With files from Sonja Puzic
This report was first published by The Canadian Press on March 29, 2024.
Canadian Press health coverage is supported by a partnership with the Canadian Medical Association. CP is solely responsible for this content.
