With excitement building over the solar eclipse set to take place on Aug. 21, anyone looking to view the rare phenomenon will need a pair of special eclipse glasses to avoid the harmful effects of staring directly at the sun.
For more important safety information, pre-order Jeff Rossen's new book "Rossen to the Rescue" here.
However, experts say that dangerous counterfeit glasses are flooding the market. Using a counterfeit pair could potentially harm your eyes to the point of causing blindness.
The issue has become so widespread that Amazon has cracked down on counterfeit sellers.
The retailer has refunded customers who bought glasses that don't meet safety standards and sent out emails recommending that customers do not use certain products to view the sight of the moon covering the sun across North America for the first time in almost a century.
TODAY national investigative correspondent Jeff Rossen put a series of glasses to the test on Monday to see which ones are safe, and also met with experts to determine what you should be looking for in a good pair of eclipse glasses.
It's also important to note that you cannot use regular sunglasses to view the eclipse, no matter how dark the lenses are on the glasses. TODAY Health spoke with experts about why it's not safe.
Rossen visited ICS Laboratories in Brunswick, Ohio, one of the only labs in America accredited to test eclipse glasses for safety, to test different pairs of glasses and see how much sunlight they allow in.
The lab has special equipment that tests the filters on eclipse glasses to determine how much light passes through, which is hard to tell with just the naked eye.
"We have some pop-up vendors who are looking to play fast and loose with certification claims, testing claims,'' Steve Pfriem of ICS told Rossen. "The general public doesn't really understand what that means and more often than not those claims aren't even accurate."
Pfriem tested a pair of samples, finding one safe to use and noting that the other pair exceeded maximum transmission requirements despite having "safe solar eclipse viewing" printed on the side of the glasses.
One sure tip that the glasses are safe for use according to Pfriem is if they have "ISO 12312-2 standard" labeled on them.
Another tip: You shouldn't be able to see your hand in front of your face while wearing the glasses. That would mean too much light is getting through the filter.
"So a third thing you could look for is when the product is actually in your hand,'' Pfriem said. "Look at the film itself and make sure that there's no pocking, bubbling or creasing. What those deformities sometimes serve to do is amplify the sun's light coming through the filter."
Here is a list provided by the American Astronomical Society of telescope and solar-filter companies that sell eclipse glasses that have been verified by an accredited testing laboratory to meet the ISO 12312-2 international safety standard.
- American Paper Optics (Eclipser) / EclipseGlasses.com / 3dglassesonline.com
- APM Telescopes (Sunfilter Glasses)*
- Baader Planetarium (AstroSolar Silver/Gold Film)* [see note]
- Celestron (EclipSmart Glasses & Viewers)
- DayStar (Solar Glasses)
- Explore Scientific (Solar Eclipse Sun Catcher Glasses)
- Halo Solar Eclipse Spectacles
- Lunt Solar Systems (SUNsafe SUNglasses) [see their unique kid-size eclipse glasses]
- Meade Instruments (EclipseView Glasses & Viewers)
- Rainbow Symphony (Eclipse Shades) [sold out]
- Seymour Solar (Helios Glasses)
- Thousand Oaks Optical (Silver-Black Polymer & SolarLite)
- TSE 17 / 110th.de (Solar Filter Foil)*
Note: Baader Planetarium's AstroSolar Safety Film and AstroSolar Photo Film, sold in the U.S. by Alpine Astronomical and Astro-Physics, are not certified to meet the ISO 12312-2 international safety standard and are not designed to work as eclipse shades or handheld solar filters. Baader's AstroSolar Silver/Gold Film, on the other hand, does meet the ISO 12312-2 safety standard for filters for eyes-only direct viewing of the Sun.