ABSTRACT
In a modern society that seems to be challenged by math, laser safety calculations provide a double-edged dilemma to the laser safety officer (LSO). An understanding of the principles behind calculations is important to the LSO; the actual performance of such calculations today is limited. In the research setting the nominal hazard zone many times is deemed to be the laser room for convenience, and optical density for laser protective eyewear can be provided by vendors. Most LSOs use software to perform safety calculations, but the LSO should be knowledgeable of the calculations involved and capable of recreating the calculations if needed. Laser safety calculation software does offer advantages to the LSO: easily obtained results and a paper document. It is extremely important to be aware that some of the formulas listed in the laser standards are empirically derived from experimental data. This means that the results of biological studies are plotted and the best mathematical fit for a line is determined and, if necessary, offset by a safety factor. The offset safety factor is not uniform across all wavelengths; it can range from a factor of 1 to 10. Therefore, as our understanding of biological effects and processes expands, exposure limits and other aspects of laser safety calculations may change. For the readers to obtain the most accurate information on these factors, they are better off referencing the latest laser American National Standards Institute (ANSI) or International Electrotechnical Commission (IEC) standard.
