What Does UV400 Mean?

Protect Yourself Against Harmful UV rays

So you keep seeing the rating “UV400” in the specs for the sunglasses you’re shopping for, but what exactly does that mean? Here’s a simple explanation from the SeaDog.

So it’s that time of year when you’re heading off to the beach to catch some rays and tan that body, but it’s also that time of year when we hear a lot of talk about making sure you’re wearing sunblock to prevent burning. Most of us are well informed about protecting ourselves against sunburn, but how much thought do you put into protecting your eyes?

The sun emits radiation, lots of it, and the most basic types of UV or “Ultra Violet” radiation to reach the earth are know as UVA, UVB and UVC. First of all, UVC radiation is the one you don’t need to worry about as these UV rays never reach the earth’s surface being absorbed by the ozone layer. So this leaves UVA and UVB and those are the ones we actually need to be concerned about.

UVA Rays make up as much as 95% of the UV radiation that reaches the surface of the earth. Studies have shown these rays cause wrinkles and lines on the skin. These rays are present with relatively equal intensity throughout the year and can also penetrate through clouds and glass. This means you need to be thinking about protecting yourself in the winter too, not just the summer. UVA Rays are not the primary cause of sunburn, that would be UVB Rays, but they are they type of rays given off in tanning beds.

UVB Rays are the primary cause of sunburn. Whereas UVA rays are prevalent year round, UVB Rays are not around with the same intensity all year, being most prevalent from the spring to the fall. However, with that being said, they still do hit you in the winter, and if your spending your winter day around snow and ice, you’ll get a double dose because they’ll reflect off shiny surfaces.

OK, so this brings us back to the original question, what is a UV400 rating when it comes to sunglasses? Sunglasses with a UV400 rating, which by the way is the American Standard for sunglass protection, means that the sunglasses will provide protection against 99% to 100% of UVA and UVB Rays, and your eyes will thank you for that. The 400 in the rating simply means the sunglasses block all rays of light up to a wavelength of 400 nanometers.

All the sunglasses found at SeaDog Jack’s carry a UV400 rating.

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