Prescription lens tint categories explained

Lens a category applies to all tint colours, grey is the most popular. Grey doesn’t distort colour and black is the biggest selling frame colour and let’s face it, it looks really cool. But there is a science to lens tints and it’s important to have an understanding of what it all means. When you buy a pair of sunglasses they come with the percentage of light transmission already selected. When you are having custom made prescription lenses you have the choice. You can select from Cat 0 to Cat 4, you may think Cat 4 is the best when actually it is completely unadvisable to use for driving for example.

So in the real world let’s take a look at each lens category and how it might be used in the world of sport. The 5 categories’ 0 to 4 refers to a band of light transmit ion, the percentage of light that passes through the lens.

Shades of grey:

  • Cat 0 lenses are either clear or have a very light tint, they are used in safety glasses, sports where you want the maximum light to pass through the lens like football and a range of other in and outdoor sports

  • Cat 1 lenses in sport are typically yellow used for low light conditions.  You would see yellow lenses in glasses and goggles for sports like skiing, shooting and cycling.

  • Cat 2 lenses in sport are most commonly amber in colour. Cat 2 lenses make a good imtermediate lens and can be used for both dull and bright days. Sports where you would see this lens are Skiing, cycling and shooting.

  • Cat 3 – is the typical sunglass lens providing protection from both visible and UV light.  These lenses will usually only allow less than 20% LVT of visible light to penetrate the lens.  This means that they will block out 80%+ of brightlight. These lenses would be used in a wide range of out door sports Cricket, fishing, golf, sailing, tennis, skiing.

  • Cat 4 – Lenses are much more specialised and are used for extreme applications. They allow only a small percentage of light to pass through the lens approw 5 to 8% LVT. The lenses are used for mediacal condition such as photophobia, after eye surgery. Other extreme uses would be at high altitude mountaineering, out in the artic.

Visible Light Transmission (VLT) - This is the measure of how much light your sunglass lens lets through to your eye and can be expressed as a percentage, therefore a VLT of 1% means very dark glasses indeed, and a VLT of 100% means all the light is getting through and the lens is, therefore, a 'clear lens'.

Rather than quote a percentage for each lens they are categorised as follows:

  • Category 0; 80-100% VLT
  • Category 1; 46-79% VLT
  • Category 2; 18-45% VLT
  • Category 3; 8-17% VLT
  • Category 4; 3-8% VLT