Product Code: ILSC2011_103

The Widely Varying Risk from Class 3R Laser Products in Light of the Revision of IEC 60825-1
Authors:
Karl Schulmeister, Seibersdorf Laboratories; Seibersdorf Austria
Presented at ILSC 2011

The current state of the characterisation of the risk from Class 2 and Class 3R laser products is discussed. We distinguish exposure to cw lasers from pulsed lasers, and we also distinguish between classification as small source (C-sub6 equal to 1) or classification as extended source. Due to the dependence of the damage threshold on exposure duration, Class 2 exposure does not appear to be able to induce retinal injury by thermal pathway even for exposure durations of several seconds. Class 2 can therefore by considered as "safe" even for the case that the blink reflex does not work. For Class 3R lasers, the risk for retinal injury varies strongly with pulse duration and source size: in the nanosecond regime, and for extended sources, the risk for injury from a Class 3R laser product is significantly greater than compared to a cw laser that was classified as small source (AEL = 5 mW). We therefore argue that it would help a consistent understanding of the risk of Class 3R products, and a treatment as relatively safe, to limit Class 3R to 5 mW and cw emission.