EN 207 is a European norm for laser safety eyewear (now superseded, together with the EN 208, by the ISO 19818:2021 standard [1]). Any laser eye protection sold within the European Community must be certified and labeled with the CE mark. According to this standard, laser safety glasses should not only absorb laser light of a given wavelength, but they should also be able to withstand a direct hit from the laser without breaking or melting, both the filter and the frame. In this respect, the European norm is more strict than the American norm (ANSI Z 136) that only regulates the required optical density. More precisely, the safety glasses should be able to withstand a continuous wave laser for 5 seconds, or 50 pulses for a pulsed laser (EN 207:2017).[2]
An EN 207 specification might read IR 315–532 LB6. Here, the letters IR indicate the laser working mode, in this case a pulsed mode. The range 315–532 indicates the wavelength range in nanometers. Finally, the scale number LB6 indicates a lower limit for the optical density, i.e. the transmittance within this wavelength range is less than 10−6.
EN 207 specifies four laser working modes:
| Working mode | Letter | Pulse length |
|---|---|---|
| Continuous wave | D | > 0.25 s |
| Pulsed mode | I | > 1 μs–0.25 s |
| Giant pulsed mode | R | > 1 ns–1 μs |
| Modelocked | M | < 1 ns |
The scale numbers range from LB1 to LB10, where the number is a lower
limit for the optical density, i.e. LBn means that OD > n, or
| Working mode | Wavelength range | Maximum laser power density |
Minimum protection level for given power* |
|---|---|---|---|
| D (continuous) | 180–315 nm | 1×10n−3 W/m2 | log(P) + 3 |
| >315–1400 nm | 1×10n+1 W/m2 | log(P) − 1 | |
| >1400 nm–1000 μm | 1×10n+3 W/m2 | log(P) − 3 | |
| I,R (pulsed) | 180–315 nm | 3×10n+1 J/m2 | log(E/3) − 1 |
| >315–1400 nm | 5×10n−3 J/m2 | log(E/5) + 3 | |
| >1400 nm–1000 μm | 1×10n+2 J/m2 | log(E) − 2 | |
| M (ultrashort pulses) | 180–315 nm | 3×10n+10 W/m2 | log(P/3) − 10 |
| >315–1400 nm | 1.5×10n−4 J/m2 | log(E/1.5) + 4 | |
| >1400 nm–1000 μm | 1×10n+11 W/m2 | log(P) − 11 | |
| *P in W/m2, E in J/m2. Level numbers should be rounded upwards. | |||
If the beam diameter differs from 1 mm a correction factor, depending on the material of the filter and frame, must be applied. Another correction factor must be used for pulsed lasers in case of repeated pulses for wavelengths above 400 nm.
, which is rounded up to 2. In other words, the safety goggles should be at least D 780 LB2.
From the scale it can be inferred that the power densities that correspond to 
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