The Optical Density or OD of laser goggles is a measure of how well the eyewear reduces the laser power at a specific wavelength or wavelength range. The below list shows the most common optical densities and the corresponding levels of attenuation. The larger the OD value the greater the level of protection.
OD 1+: >10X reduction in laser power
OD 2+: >100X reduction
OD 3+: >1000X reduction
OD 4+: >10,000X reduction
OD 5+: >100,000X reduction
OD 6+: >1,000,000X reduction
OD 7+: >10,000,000X reduction
Higher optical densities are desirable when you do not need to see the laser for alignment purposes. If you need to be able to see the laser beam while reducing it to an eye safe level then a more precise calculation will be required.
If you have any questions over your requirements feel free to contact us and one of our laser safety experts will be happy to assist.