Did you know that some shades are not suitable for wearing when driving or cycling? Or that there is a CE mark to check they’ve been approved in the UK?
This is to make sure that all sunglass frames are strong (within reason) and sweat resistant with lenses that are shatterproof, scratch resistant and giving good protection against harmful ultra-violet light.
All sunglasses sold in the UK need the CE mark and are graded into five categories – 0 to 4 – to show how dark the tint is, or more specifically, how much visible light they let through.
Categories of Sunglasses
Category 0 specs allow 80% to 100% of visible light through and are fine for driving at any time.
Categories 1, 2 and 3 are progressively darker tints, shielding against brighter levels of sunshine, and while they are all fine for daylight driving, none of them should be worn if you’re driving at night.
The darkest is category 4, which lets just 3% to 8% of the light through. These are very dark, like ski goggles. They are so dark that they should not be used for driving at any time.
NB: Category 4 sunglasses are unsuitable for driving.
How to Choose the Right Sunglasses
Sunglasses on sale in shops such as chemists or opticians are likely to have the CE label and are marked with the category – normally on the arm.
However, online shoppers beware; a look through several shopping websites revealed that very few sellers display the tint category or any symbol, so you have no way of telling whether the glasses are suitable for driving until they arrive.
A few are advertised as category 4 and suggested as being good for cyclists, although the official standard states they are “not suitable for driving and road use.”
As we see it, common sense would say that if they’re too dark for driving, they’re too dark for cycling.
Photo-chromic glasses aren’t marked but they should be fine for most cars because they respond to ultraviolet light to darken. Car windows block UV light, so the glasses will stay more or less clear.
Watch out if you drive a convertible though, because once the roof’s down the glasses will darken, but at their darkest they still allow about 20% of light through, putting them around category 2 or 3. Just be aware that they will stay dark for quite a while if you drive into a tunnel or underpass or a long stretch of shadows.
So, while the sun stays shining, check the category number before you drive and make sure your shades keep you safe as well as cool.
If your sunglasses are too old to have any CE markings at all, it sounds like it’s time to go shopping for the right sunglasses, armed with this knowledge.
Needless to say, for the best advice about the right sunglasses for your eyes, ask your optician at your next visit.