OD-values are merely absorption values, while the protection levels defined in the norm DIN EN 207 are based on endurance performance and laser stress tests.
OD-values, as found on laser safety products, manufactured and sold outside of the European Union, are merely a statement about the absorption, depending on the wavelength, as light passes through the medium. For a factual statement for the given laser protection, the thermodynamic effects of the impacting laser ray must not be neglected. This key statement, regarding the laser protection, is given by following the laser stress tests defined by the norm DIN EN 207. The OD-Values may be higher than the values of the protection level, given by the DIN EN 207, but they are not a valid statement. The difference in price between certified and non-certified laser safety glasses should be made up against an intact eyesight.