ABSTRACT
At the core of all laser safety guidelines is the concept of maximum permissible exposure (MPE), defined as the level of laser radiation to which an unprotected person may be exposed without adverse biological changes in the eye or skin (American National Standards Institute [ANSI], 2007; International Commission on NonIonizing Radiation Protection [ICNIRP], 2000). While the concept of MPE is quite simple, the reality is that the MPE is multidimensional, dependent on the wavelength and duration of the exposure, and modulated by the presence of repetitive pulses and diffusers or optics, which might increase the size of the beam at the target tissue. The guidelines include several pages of rules, tables, charts, conditionals, and caveats for the computation of the MPE for all reasonably foreseeable laser applications except, of course, the one the user might have in mind.
