Safety eyewear is a regulated product. EN 166 (Europe) marks the frame and lens with the manufacturer, optical class, impact grade (S, F, B, A) and fields of use (3 liquids, 4 dust, 5 gas, 8 electric arc, 9 molten metal). ANSI Z87.1 (United States) marks Z87 for basic impact and Z87+ for high impact. AS/NZS 1337 and CSA Z94.3 apply in Australasia and Canada.
Prescription safety eyewear is a specialist business: frames tested to the standard with lenses in polycarbonate or Trivex, often supplied through occupational programmes to employers. Welding uses shade numbers (DIN scale); laser protection uses optical density at specific wavelengths.
Buyers should insist on certification from an accredited body, test reports for the batch, and the correct markings on every frame and lens; unmarked safety eyewear cannot legally be sold as such in most markets.