I am sure that many times you have wondered if your sunglasses are good, if you have the 100% protection against the ultraviolet that promises the seller and / or manufacturer.

The safest way to buy good sunglasses, which have 100% ultraviolet protection, is to do it in opticians and authorized establishments.

But I know that many of you do it online, and that many times you even risk products bought abroad, in online stores of dubious reliability.

That is why I want to give you some advice to buy sunglasses that we are sure to have total protection against harmful solar radiation.

It is obvious that you cannot buy them in the markets, nor bazaars, nor top manta, that is well known. But if we apply this to the subject online, do not buy excessively cheap sunglasses. Nobody thinks you can sell an Oakley or a Rayban for less than 40 euros. It is a truism, but no one gives hard to pesetas.

So even if you go looking for deals the first thing is to buy at a reasonable price.

Another thing is the new brands of "low cost" sunglasses. Many of these glasses do sell for less than 30 euros, and almost certainly I would say that protection against ultraviolet is good. In this type of glasses you are not paying the mark of prestige sunglasses with years of trajectory. That allows them to lower costs.

Nevertheless, I would subject to any type of spectacle of this type or of the bought ones in places with doubtful reputation, to the following tests.

· -Test with UV lamp and photochromic crystal

· -Test with UV analyzer

The first test is very easy, and you can do it at home. It is about acquiring an ultraviolet flashlight, which can be easily obtained on the internet, and a photochromic lens. You can also get it on the internet, later on I'll tell you where.

The test consists of the following:

A photochromatic crystal is one that reacts to ultraviolet light passing from a clear to a dark state by the action of said radiation. When this radiation is not present, the crystal returns to its initial state with a light color.

We would use the ultraviolet lantern as follows:

· -We would like the sun lens that we want to check if it has 100% sun protection in front of the photochromic lens.

- Next we would turn on the flashlight pointing towards the sun lens that we want to check if it is good.

· "Now we check if the photochromic lens has been obscured by the action of the Ultraviolet flashlight.

- If it has darkened, it is that the sun lens that we are checking is not good, it does not have 100% ultraviolet protection. Why? Because it has passed this UV and in this way the photochromic lens has darkened.

· -If the photochromic lens has not darkened, the sunglasses are good because they have blocked the ultraviolet coming from the lamp.

If you watch this video, you will understand much better.

Another way to know if a sunglass is good, if you have 100% Ultraviolet protection is to pass the lenses through a UV analyzer.

A UV analyzer is a device that serves precisely for that, to analyze the degree of protection UltraVioleta that the crystals have. 

Obviously I do not think you have one at home, it is an expensive device, which is present in optical shops, and in some optics than another.

The lens is glued to the UV lamp of the analyzer, and the device calibrates the amount of radiation protection the tested lens has.

I leave you a video of a company with which I collaborate, so you can see what it is.

Before I told you, I would show you where to get a photochromic lenses to do the test. And as I told you that I collaborate with Sunglasses Restorer, I leave you a couple of links where you can get them. In this link I tell you what are the photochromic lenses and, within the web you can find them easily. For the one who reads from the other side of the puddle, this is a link Oakley Replacement Lenses And if some German happens to read me, this is the web in Goethe's language Oakley Ersatzgläser I hope you liked the article and now you can differentiate the