Can you really go blind if you look at an eclipse of the sun without special glasses?

On July 2, several places in Latin America will enjoy a total solar eclipse.

No matter where you are, you'll want to see it and that's fine. 

Any astronomer will tell you that you should take this opportunity because it can be unique. And your health is not at risk from the simple fact of being on the street during the eclipse.

But there is something you should not do: look at the Sun with the 'naked eye', without special glasses or some kind of special protection. Do not do it. Seriously.

There are only two moments in which you can observe the Sun like this, without protection, because its brightness is reduced:

·        If you are on the path of the totality of the phenomenon, in which the Sun will be completely covered by the Moon.

·        During those two minutes or less in which the Sun will be completely covered

At any other time or place, sunlight can not only be uncomfortable, but dangerous.

What happens if you ignore the warnings?

Your face is not going to melt, but your eyes could suffer severe damage. And yes, you could go blind. Looking directly at the powerful glow of the sun can damage the retina, the part of the eye that is sensitive to light.

The retina will turn light into an electrical impulse that the brain can understand, but there is something the brain cannot grasp: pain. So even if you think that seeing it for just a second is worth it, do not do it. 

There is no way to know that you saw the Sun for a long time. Any amount can be enough to hurt you.

Why do you need special glasses to see the eclipse?

We know that you like them. It's your sunglasses. But they will not serve you to see the eclipse. You will need special glasses, regulated with an international security standard. 

They are cheap and they are easily obtained, and even in some libraries, they are giving them for free.

It does not matter if you use glasses made with cardboard or a portable card with a rectangle cut to see the phenomenon, the most important thing is the filter.

"Filters that have the ISO 12312-2 standard reduce the brightness of the sun to a safe and comfortable level, such as that achieved with a full moon, and block harmful ultraviolet and infrared radiation," says Rick Fienberg, of the Astronomical Society of the United States.

"Sunscreens that meet this standard are almost 100,000 times darker than ordinary sunglasses, and those glasses do not block infrared rays."

The problem is that the market is flooded with glasses that are not safe but have a label that says they meet the ISO standard.

"The only way to know they are safe is to verify that they come from a reputable manufacturer with a good reputation or that they are sold by an authorized dealer," the Astronomical Society said in a recent statement. 

The organization also has an updated list of special glasses to see eclipses and vendors.

To check your safety, the only thing you can see through a safe sunscreen is the Sun itself. If you look at the Sun and it shines a lot, if it is out of focus or if it is surrounded by a layer of fog, or if you can see normal lights, like those in houses, then that filter is not safe.

And be careful, because if you want to reuse eclipse glasses that are more than three years old, they were made before the last international safety standard. To the trash!

If you plan to see the eclipse through a camera, a telescope or binoculars, buy sunscreen to put it at the end of the lens. But do not wear glasses to eclipse while watching any of those objects, because the concentration of sun rays can damage the filter and go directly to your eyes and cause them a severe injury.

These are some important safety tips, according to the Astronomical Society of the United States:

·        Always check your sunscreen before using it; If it is scratched, punctured, torn or has any other damage, discard it.

·        Always supervise children who use sunscreen.

·        If you normally wear glasses, leave them on. Put the special glasses on top of them or hold them right in front.

·        Cover your eyes with your special glasses to see the eclipse or your sunscreen before seeing the sunshine. After looking at it, turn around and take them off, do not take them off while you are watching the sun.

·        If you are within the path of the entire eclipse, take off the sunscreen only when the Moon completely covers the sun's brightness and suddenly everything darkens. As soon as the sunlight begins to appear again, put back the sunscreen or special glasses.

·        If you are out of the way of the entire eclipse, you should always use a safe sunscreen.

And do not worry about your pet. Although they may experience strange behavior during the eclipse, animals know how to look at the Sun better than humans.