What the different lens categories mean
11th Feb 2025
We thought we'd round off the last couple of posts on lenses by looking at what the different lens categories mean. It's true we don’t always provide the density of tint number (Cat. 0 to Cat. 4) in our product descriptions because some brands we sell do not provide this information. The Category number equates to a percentage of the VLT (Visible Light Transmission) - basically how much light the lens lets through, as follows:
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| 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 |
The following is a general guide to the Categories that apply to different lens colours:
- Category 0 – Clear, Light Yellow, Pale Orange & Yellow
- Category 1 – Rose, Orange & Vermilion
- Category 2 – Purple, Red, Amber & Light Brown
- Category 3 – ‘Standard’ Grey & Brown
- Category 4 – Dark Grey & Dark Brown
Almost all the grey and brown lens sunglasses we sell are Category 3 and suitable for use in strong sun conditions. We always clearly identify Category 4 sunglasses because these have specific uses e.g. high altitude walking, climbing and skiing. They are also good for anyone that has eyes sensitive to bright light but it's important to know that you mustn't use Category 4 lenses for driving (they are too dark for driving).