Safety Glasses and EN 166 Eye Protection: Don't Risk Your Sight
Safety glasses certified to EN 166 are the starting point for protecting eyes at work, covering everything from grinding sparks to dust and chemical splashes. Eyes are irreplaceable, yet eye injuries remain common in workshops, on sites and in factories, usually from flying particles, dust, chemical splashes or UV exposure. The frustrating part is that almost all of them are preventable with the right eye protection.
What does EN 166 cover?
EN 166 is the baseline standard for eye protection used in the UK and Europe. It covers safety spectacles, goggles and face shields, and sets requirements for optical quality, robustness and resistance to impact. Every compliant frame and lens carries markings that tell you what it has been tested for.
The impact symbols are the ones most buyers need. Check both the frame and the lens, because where they differ, the lower rating applies to the whole protector.
| Marking | What it means | Typically found on |
|---|---|---|
| S | Increased robustness, no particle impact rating | Basic spectacles |
| F | Low-energy impact (45 m/s) | Safety spectacles, goggles and face shields |
| B | Medium-energy impact (120 m/s) | Goggles and face shields |
| A | High-energy impact (190 m/s) | Face shields only |
Other useful markings include 3 for liquid droplets and splashes, 4 for large dust particles, 5 for gas and fine dust, and 9 for molten metal and hot solids.
Safety spectacles, goggles or face shields?
Safety spectacles suit general work with impact risks such as grinding, drilling, cutting and strimming. Modern styles are lightweight, wraparound and genuinely comfortable, a world away from the clunky designs of the past.
Safety goggles seal around the eyes, protecting against dust clouds, liquid splashes and fine particles that spectacles can't stop. Indirect-vent goggles suit splash and dust work, and they pair well with a respirator; our guide to FFP1, FFP2 and FFP3 dust masks explains how to choose one.
Face shields add full-face coverage for high-risk tasks like using cutting discs or handling chemicals. Many fit onto a helmet brow guard, so check compatibility with your hard hats and head protection. For heavy impact work, wear spectacles or goggles under the shield as well.
Welding and torch cutting are a separate case. They need filter lenses with the correct shade number, so choose from dedicated welding protection rather than general-purpose glasses.
Choosing the right lens tint and coating
Lens choice matters too. Clear lenses suit general indoor use, smoke-tinted lenses cut glare for outdoor work, and yellow lenses improve contrast in low light. Avoid dark tints indoors or for anyone moving between bright yards and dim buildings, as reduced vision creates its own hazards.
Anti-mist and anti-scratch coatings are well worth having. Under EN 166 these appear as N (resistance to fogging) and K (resistance to surface damage by fine particles). A fogged or scratched lens gets pushed up onto the forehead, and unworn PPE protects nobody.
Prescription wearers, fit and care
Everyday prescription glasses are not safety eyewear, however sturdy they look. If your team wear prescription glasses, look for over-spectacle styles that sit comfortably over their own frames, or consider prescription safety eyewear for regular users.
Fit makes a big difference to whether glasses stay on. Offer a choice of styles and sizes, check they work alongside ear defenders and masks from your wider PPE kit, and involve wearers in the choice. Your risk assessment should set out where eye protection is needed and which type, and it must be provided free of charge.
Keep eye protection clean, store it in a case or pouch, and replace scratched lenses promptly. Clean lenses with water or a suitable lens cleaner and a soft cloth rather than a dry rag or sleeve, which grinds dust into the surface. Replace any pair with cracked frames, loose side shields or a lens that has taken a heavy impact.
Quick answers
What does EN 166 mean on safety glasses?
It shows the eyewear has been tested to the European standard for personal eye protection. The markings on the frame and lens show the impact rating (S, F, B or A) and any other protection, such as against splashes or fine dust.
Are safety glasses or goggles better for dust?
Goggles are better for dust clouds and fine particles because they seal around the eyes. Safety spectacles protect against impact from the front and sides but leave gaps around the edges.
Can I wear my normal glasses instead of safety glasses?
No. Ordinary prescription glasses are not tested or marked to EN 166. Use over-spectacle safety glasses or prescription safety eyewear instead.
Browse our EN 166 eye protection range for safety spectacles, goggles and accessories, or contact our team if you need help matching eyewear to the task.
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