Class 1
Class 1 laser products are safe in normal use under reasonably foreseeable conditions. There are two types of Class 1 laser products:
Class 1M
Class 1M laser products are safe in normal use provided lenses and/or mirrors or other such optical devices are not used to modify the laser beam or to assist viewing. Control of unfiltered optical viewing aids is therefore generally sufficient to ensure safety.
Class 2
Class 2 laser products emit low levels of visible radiation (i.e. in the wavelength range 0.4 to 0.7 μm) and are safe in normal use by virtue of the natural aversion response of the eye to bright light, which is deemed to limit the duration of exposure to 0.25 s. Nevertheless they present a severe dazzle hazard. For a Continuous Wave (CW) laser the Class 2 AEL is 1 mW.
Class 2M
Class 2M laser products emit visible radiation (i.e. in the wavelength range 0.4 to 0.7 μm) and are safe in normal use by virtue of the natural aversion response of the eye to bright light provided lenses and/or mirrors or other such optical devices are not used to modify the laser beam or to assist viewing. Control of unfiltered optical viewing aids is therefore generally sufficient to ensure safety. Nevertheless, they present a severe dazzle hazard.
Class 3R
Class 3R laser products are unsafe for direct viewing of the laser beam, whether in aided or unaided viewing, but for which the risk is still regarded as low. The AEL for Class 3R is 5 times greater than for Class 1 or, for visible beam lasers, 5 times greater than for Class 2. This means that direct ocular exposure to the output of a Class 3R laser carries a low (i.e. not entirely negligible) risk of injury. This contrasts with Class 1M and 2M lasers for which naked eye viewing is safe but with viewing aids the risk of injury can be high.
