The 2024 total solar eclipse is happening today: Here are all the health risks and warnings to be wary of

Here are some health tips for staying safe during the major event.

This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis or treatment. Contact a qualified medical professional before engaging in any physical activity, or making any changes to your diet, medication or lifestyle.

People watch solar eclipse using protective lenses in Buenos Aires, Argentina on Dec. 14, 2020. The total solar eclipse was visible in parts of Chile and Argentina. (Photo by Mariano Gabriel Sanchez/Anadolu Agency via Getty Images)
A total solar eclipse will be viewable for many Canadians on April 8. Here's all you need to know, including health risks and how to spot fake solar eclipse glasses. (Photo by Mariano Gabriel Sanchez/Anadolu Agency via Getty Images)

Many Canadians are gearing up for a once-in-lifetime experience: Today, a total solar eclipse will cross North America, passing over Mexico, the United States and Canada.

While solar eclipses generally occur every 18 months, a large portion of them are out of sight for most Canadians. That's because the majority of solar eclipses spend roughly 60 per cent of the time over the Pacific and Atlantic oceans. That's why the upcoming total solar eclipse is making headlines, as it'll spend an extended period of time over several cities. That includes Kingston, Ont., which will have an estimated two-hour period to witness the entirety of the eclipse.

"For one specific city on this planet, eclipses happen roughly every 366 years or so. It's more than [a] once-in-a-lifetime thing," Nikhil Arora, a post-doctoral fellow in the department of physics at Queen's University and the school's eclipse outreach coordinator, tells Yahoo Canada. That's because the next total eclipse isn't expected until August 2044.

While the impending eclipse is undoubtedly exciting, there are some safety concerns and hazards that come with the event — both expected and slightly surprising. Below, read everything you need to know about potential health risks, how to spot fake solar eclipse glasses and more so we can all safely enjoy the total solar eclipse — without any burned retinas.

A total solar eclipse occurs when the moon passes between the Sun and Earth. (Photo via Getty Images)
A total solar eclipse occurs when the moon passes between the Sun and Earth. (Photo via Getty Images)

What is a total solar eclipse?

According to NASA, a total solar eclipse occurs when the moon passes between the Sun and Earth, completely blocking the sun and bathing the earth in darkness, as if it's dawn or dusk.

What are some health risks when it comes to a solar eclipse?

A big event like a solar eclipse often means mass gatherings. It's a concern Dr. Piotr Oglaza, medical officer of health for Kingston, Frontenac, and Lennox and Addington says the region is taking into consideration when planning for the weekend of the eclipse.

"Any time we are expecting a number of visitors coming into the region for this event, we might see a significant traffic congestion, potentially gridlocks," Oglaza tells Yahoo Canada.

While a little bit of traffic might seem like a bummer at the most, as Oglaza notes, it can have an impact on people's health, affecting whether or not locals can access basic supplies.

"Let's say somebody relies on medication. They may or may not be able to get to the pharmacy because of the traffic congestion," Oglaza says. "So, there's some very unique aspects [and] people can prepare for that."

Despite the fact the eclipse is taking place outdoors, a large number of people concentrated in one area can also increase the risk of both injury and transmission of communicable diseases, like measles or Avian Influenza. Oglaza advises individuals take necessary precautions, like distancing or wearing masks especially when in enclosed spaces, and ensuring they're up-to-date on vaccines for diseases like measles.

A person wears protective glasses to watch a partial hybrid solar eclipse at Ismail Marzuki Park in Jakarta, Indonesia on April 20, 2023. The hybrid solar eclipse is a unique type of solar eclipse that experiences two phases simultaneously, namely the ring phase and the total phase. (Photo by Eko Siswono Toyudho/Anadolu Agency via Getty Images)
Wearing a mark in an enclosed space, such as areas that might be full of people viewing the eclipse, might be a good idea. (Photo by Eko Siswono Toyudho/Anadolu Agency via Getty Images)

"The transmission is much greater in confined spaces, so being outdoors is probably the safest way of gathering, and so that's hopefully going to mitigate some of the risk," Oglaza says. "But if [people] are staying or coming to the community, they might be also congregating indoors before or after the event, depending when they plan to arrive or leave that area."

Still, a major health concern related to a solar eclipse is one that's not all that surprising: "The biggest risk [is] staring directly into the sun," says Canadian Associate of Optometrists's president Dr. Martin Spiro. "And this is a risk whether it be the day of an eclipse or not."

Why is a solar eclipse so dangerous to look at?

"Damaging of the retina is definitely the most serious risk," Spiro says of staring directly into an eclipse. "And the one that could cause permanent vision loss."

According to Spiro, looking directly at an eclipse can burn a pattern similar to the eclipse onto your retina, causing central vision loss, a condition called solar retinopathy. "In extreme cases, [this would include] difficulty with fine vision, like reading or recognizing faces," Spiro adds.

There's also a higher physical risk for children, the optometrist notes, due to the fact that their pupils are larger in size, leading to more exposition that could come in off the sun.

These effects may not be instantaneous, appearing hours or even days after the eclipse and the effect may be dictated by how long one looks directly at the sun. "The longer and the more exposed we are and looking at [the sun], the higher the possibility of permanent damage to the back of the eye," Spiro says. If you do think your eyes may have been affected during an eclipse, it's best to immediately contact an optometrist.

Young girl with red hair watching the annular solar eclipse with special viewing glasses.
Children have to take extra precautions when viewing an eclipse. (Photo via Getty Images)

Is it worse than looking directly at the sun on a regular day?

It's never good to look directly into the sun, mostly because it can cause permanent damage to the back of the eye, potentially burning your retina depending on the length of time one stares at the sun and its intensity. While risky on a regular day, due to the fact that humans don't have sensors on their retinas to indicate whether they're being affected, the glare and brightness from the sun causes us to become uncomfortable and naturally turn away.

With an eclipse, when the sun is partially blocked, that natural inclination is reduced, meaning we may be less likely to turn away from the sun or feel like it's safe to stare at for longer. But the potential damage remains the same, whether or not there's a glare.

"It's less uncomfortable to look at the sun during the eclipse, but the damage is all the same there — and that's where the safety risks happen," Spiros says.

How can I safely watch a solar eclipse?

The good thing is, there are a lot of ways — and available instruments — to help you safely view this historic occurrence. The safest way to view the eclipse is with a pair of optometrist-approved solar eclipse viewers. These are glasses specifically approved for eclipse viewing and fall within the international standard ISO 12312-2.

"Regular sunglasses, even those with very dark tint, will not be able to protect the eyes," Olgaza says. "And it's certainly not safe to view the eclipse from a camera, phone lens or telescope."

Eclipse glasses pointed towards the sky. (Photo via Getty Images)
While you might be able to snag a cheap pair of glasses at some retailers, it's best to purchase one from a list of reputable vendors. (Photo via Getty Images)

Where you purchase these viewers matters. While you can find eclipse glasses on Amazon for a steal, Spiro advises purchasing from reputable sources. The American Astronomical Society currently has a list of reputable vendors on its website. In addition, many local libraries and universities across the country are offering free glasses for a limited time to local residents. It's best to stock up in advance and consult your optometrist if you have any concerns.

When it comes to viewing the eclipse with children, Spiro notes it's important to go through how to properly use the glasses. "How we use them is you put on the eclipse glasses first, while not looking at the sun, and then look at the sun," he advises. To remove your glasses, Spiro recommends first turning away from the sun and then removing them.

"If proper safety precautions are taken into account, it's definitely not something I shudder at and fear [as an optometrist]," Spiro says. "We encourage everyone to enjoy it, because it's a very worthwhile phenomenon to partake in."

How can I tell if solar eclipse glasses are legitimate?

According to a Global News report, as the solar eclipse nears, there's a surge in counterfeit eclipse glasses on the market, posing a significant risk to consumers. Fake glasses may not provide adequate protection, leading to potential eye damage when observing the solar phenomena.

The American Astronomical Society issued a warning last week saying fake eclipse glasses were "polluting the marketplace." In February, Amazon pulled counterfeit product listings, while a spokesperson told Global News, "it continuously monitor its store and takes action to maintain a safe selection for customers, including removing non-compliant products."

Experts emphasized the importance of buying glasses that meet the ISO 12312-2 international standard for safe solar viewing. One option for Canadians are the Soluna Solar Eclipse Glasses, produced in the USA by NASA-approved manufacturer American Paper Optics. The product is also recognized by the American Astronomical Society and verified for authenticity through the Amazon Transparency Program.

The Soluna glasses filter 100% of harmful ultra-violet and 99.999% of intense visible light. 

$30 at Amazon

According to the AAS, you shouldn't be able to see anything through proper eclipse glasses. You should only be able to faintly see very bright lights. "If you can see anything else, such as household furnishings or pictures on the wall, your glasses aren't dark enough for solar viewing," the agency warned.

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