Choosing Safety Glasses - Spectacles or Goggles?
The right eye protection depends on the hazard, the fit and the marking. This guide explains the difference between safety spectacles and goggles, the EN 166 codes and the coatings for scratch resistance (K) and anti-fog (N).
View safety glassesSpectacles or goggles - which suits the job?
The shape follows the hazard. Safety spectacles sit like normal glasses and shield you from particles flying in from the front. Goggles seal all around the eye and add protection against dust, splashes and gases from the side.
Spectacles are light and comfortable for assembly, wood or metal work with a low splash risk. Goggles become mandatory as soon as liquids, fine dust or chemicals are involved, because only they close tightly around the eye socket.
- Spectacles: light, well ventilated, ideal against frontal mechanical hazards.
- Goggles: fully sealed, for dust, splashes and chemicals.
- Over-goggles: fit over prescription glasses.
- For sparks and molten metal choose indirect ventilation.
How to combine eye and hearing protection correctly at the workplace.
Read the guideHow do I read the EN 166 marking?
Every certified pair carries a code on the frame and on the lens. The lens shows the optical class and the mechanical strength first, the frame carries the maker and the standard EN 166. At a glance you can tell what the eyewear protects against.
The letters F, B and A stand for rising impact energy: F withstands particles at 45 m/s, B at 120 m/s and A at 190 m/s. A leading S means increased robustness, and a T after the letter (for example FT) means it was tested at extreme temperatures from -5 to +55 °C.
Scratch resistant and fog free - what matters?
Two extra codes decide everyday comfort: K stands for increased surface scratch resistance, N for anti-fog. A pair marked KN combines both and stays clear and tough through temperature changes or hard physical work.
- K (scratch resistance): tested by the sand-trickle method, guards against dull scratches.
- N (anti-fog): stops fogging when moving between warm and cold and under exertion.
- Polycarbonate lenses offer high impact strength and UV protection up to 400 nm.
- Tinted lenses outdoors only - indoors the tint cuts vision too much.
Polycarbonate is today's standard: shatterproof, light and with a built-in UV filter. For aggressive chemicals there are also acetate lenses, which are more chemically resistant but less impact resistant.
Frequently asked questions
What do the letters F, B and A on safety glasses mean?
They indicate the mechanical strength: F withstands particles at 45 m/s, B at 120 m/s and A at 190 m/s. A offers the highest protection against high-velocity particles.
What do the codes K and N stand for?
K marks an increased scratch resistance of the lens, N an anti-fog coating. Eyewear marked KN combines both properties and stays clear and robust for longer.
When do I need goggles instead of spectacles?
As soon as liquids, fine dust or chemicals occur, because only goggles seal fully around the eye. Spectacles mainly protect against particles coming from the front.
Which optical class should safety glasses have?
For continuous wear choose optical class 1, as it is distortion free and does not tire the eyes. Classes 2 and 3 are meant only for short use.
Looking for the right safety glasses?
We supply spectacles and goggles to EN 166 - with scratch protection (K) and anti-fog (N), optical class 1 and a UV filter.
Certified to EN 166
Every model meets the European core standard for eye protection.
K and N available
Scratch resistant and anti-fog coatings for clear vision.
Optical class 1
Distortion free and suitable for all-day wear.
Expert advice
Our specialists help with shape and marking selection.