Editor's note: this story has been updated to include five more manufacturers approved by the AAS

Both NASA and The American Astronomical Society are warning of fake glasses flooding the market place, including online stores. What do they mean by fake? It means glasses are being sold as "eclipse glasses" and marked as being safe to use for viewing the eclipse when, in fact, they do not provide adequate protection for your eyes.

RELATED: 'Eclipse Blindness' is a Real Thing. Here's How to Watch the Solar Eclipse Safely

So, how can you tell legitimate glasses from fake ones? Here's what you need to look for.

NASA officials say only these five manufacturers make certified, approved eclipse glasses:

Baader Planetarium
Rainbow Symphony
Thousand Oaks Optical
TSE 17
American Paper Optics

In addition to these five, The American Astronomical Society recognizes the following manufacturers as safe:

The manufacturer name and address should be printed on the glasses — be sure it’s one recommended by NASA or The American Astronomical Society.

Previous guidance from NASA had recommended consumer make sure glasses have the ISO number 12312-2 printed on them. However, some fakes are printing that on their glasses despite not meeting the requirements. So, do not rely on seeing "ISO number 12312-2" on the glasses. Instead, make sure they are from a recommended manufacturer.

And finally, look through the glasses before you get them. If you look through them and you can actually see things, they are NOT legit. If you look through them, and you can see the ground or see your hand in front of your face, you can be sure they are fake.

Before you worry about going out to get a pair, know that many viewing locations and events will be providing glasses free of charge. If you're planning to view the eclipse at a watch event, check to see if they will be providing glasses.

RELATED: View the Eclipse Safely With or Without Glasses. Here's How.

Find News 19's full eclipse coverage HERE.