When you buy a pair of sunglasses it’ll usually mention something about the category number. If you’ve ever wondered what this means, read on because we explain it all.

We’re deep in throes of summer which only means one thing: making sure you’re efficiently protected from the sun. Did you know that simply upgrading to our Gold or Platinum lens packages protects your eyes from UV400 rays? This means your eyes are protected from all UV rays with wavelengths up to 400 nanometres. Or did you know that adding any of our sunglasses tints to your frames makes them prescription sunglasses for extra sun protection? Opt for sunglasses tints and not only will you be protected from UV rays, but you’ll also receive category 3 protection. Curious about what that really means? Let us explain.

Sunglass lenses tend to come in four categories: 1, 2, 3, and 4. Each category signals the strength of the lens, what colour it usually is and typically what light conditions it is best suited for. Our table below breaks it down.

Category Characteristics Colour Suitable for…
0 NO TINTS:- typically do not block sunlight or UV light but our Gold and Platinum lens packages block 100% of UV400 CLEAR Everyday wear, fashion, prescription
1 LIGHT TINTS:- block low levels of light YELLOW/PALE ORANGE Fashion purposes
2 MEDIUM TINTS:- block average levels of sunlight without distorting vision ORANGE/RED/LIGHT BROWN Fashion purposes, everyday wear
3 DARK TINTS:- block about 80% of light and offers extra protection from UV and blue light GREY/ BROWN Playing sports, sunny weather conditions, the beach
4 VERY DARK TINTS:- not be worn at night or while driving as they let in very little light DARK GREY/ DARK BROWN Exposure to very strong light

You can usually find the lens category of a pair of sunglasses in its description.

So why have sunglasses in the first place?

Well, while upgrading your clear lenses to one of our UV blocking packages will ensure your eyes are protected from harmful UV rays, it’s the coloured lenses that make the real difference. Different coloured lenses affect the way we see and help ease visual comfort. Think of it like this: on a sunny day you shield your eyes with your hand which creates a shadow. This shadow darkens your vision, making it easier to see. In a similar way, dark coloured lenses do the same thing – meaning your hand gets a rest!

Photo: Dan Gold

Wait, there’s more

As well as lens categories, there’s another thing to know: VLT. VLT (Visible Light Transmission) is written as a percentage and is a measure of how much light your sunglasses let in. The general rule of thumb is that the higher the percentage, the more light it lets in and the lower the percentage, the less light it lets in. As such, lenses in category 0 lets in 80-100% of light while lenses in category 4 only let in about 3-8% of light. See below for a rough estimate:

Category 0: 80-100%

Category 1:46-79%

Category 2: 18-45%

Category 3: 8-18%

Category 4: 3-18%

All our frames are ready to be turned into prescription sunglasses (and protected from UV rays), so there’s no excuse to not protect your eyes this summer. Check out our wide range of frames now and have fun in the sun.

Also, for more information on UVA, UVB and UVC rays, make sure you check out our previous post.

Top image: Dan Gold