Health Minute: Eclipse safety

(CNN) - It will be the longest, most visible solar eclipse in more than a century. On April 8th, the moon will block out the sun but watching this without proper protection can lead to eye damage, even permanent vision loss.

Remember the total solar eclipse in 2017?

Well, the one coming up on April 8 will be longer and the last to be visible from the continental U.S. until the year 2044.

Just like the last one, protecting your eyes is critical.

"It is not enough just to wear regular old sunglasses for these eclipse," said Dr. Nicole Bajic, Ophthalmologist, Cleveland Clinic.

That's damage to your retina. It can cause blind spots in vision and decreased vision. Depending on the extent of damage, it can be temporary or permanent.

"You need to wear proper eclipse glasses with the solar filter iso 12312-2," said Dr. Bajic.

You'll find that printed on the inside of the eclipse glasses.

Unfortunately, there are counterfeit glasses out there.

Before buying a pair, NASA recommends checking the American Astronomical Society's list of approved solar viewers making sure the seller is listed on the website.

After buying glasses, check them, there should be no scratches or tears.

And if looking at the eclipse through binoculars, a camera, or a telescope, a certified solar filter on the front of the instrument is needed to protect eyes.

"It's not enough to just put, you know, eclipse glasses over. And in fact, that's actually dangerous because if you put eclipse glasses over a telescope or, you know, some other device, you can actually burn a hole through the glasses and lead to direct injury," said Dr. Bajic.

There are also other ways to safely view the solar eclipse.

NASA has directions on how to make a pinhole projector on its website.

The agency says there's also the indirect viewing method, which does not involve looking directly at the sun.

This method projects the sunlight onto another surface by using materials around your house, or even your hands.