Laser effects on vision and ocular exposure limits

Laser radiation poses significant risks to vision when the eye is located within the beam (intrabeam viewing), and occupational exposure limits (ELs) have been developed for these conditions. Under special circumstances, viewing even a diffuse reflection can be hazardous. The potential hazards of laser exposure vary significantly with wavelength and exposure duration. Recommended ELs have been published by a number of organizations, including the American Conference of Governmental Industrial Hygienists, the American National Standards Institute accredited committee Z-136 of the Laser Institute of America, the International Non-Ionizing Radiation Committee of the International Radiation Protection Association, and the International Electrotechnical Commission. Most of the ELs are equivalent in these standards or guidelines. Recent efforts have amended these standards or guidelines to take into account new information relating to viewing extended sources, ultraviolet lasers, and infrared lasers. Of particular note has been the concern that ELs in the 1.2- to 3.0-μm spectral region-which were initially derived for simplicity in expression-were greatly overconservative. Today, because of the development of lasers in this spectral region, these standards may needlessly inhibit growth of new infrared laser technology. With recent research, it is now possible to raise some limits.