Laser Safety deals with the safe use of lasers to minimise the risk of laser accidents particularly those involving the eye. The use and sale of lasers are governed by various laser safety regulations. For Australia and New Zealand the laser safety standards are AS/NZS 2211.1:2004, for Europe they are EN 60825-1, IEC 60825-1 and the US laser safety standards are US FDA 1040.10.
The various laser safety standards categorise lasers from Class 1 being the least hazardous through to Class 2, Class 2M, Class 3R, Class 3B and Class 4 which is the most hazardous. The various laser safety standards outline the requirements for each laser classification in terms of manufacturing and the requirements of laser safety goggles.
Lasers primarily cause damage by means of thermal effects. Damage to the eye can occur with even very moderately powered lasers via the laser entering the pupil and focussing onto the retina and destroying the Photoreceptor Cells. Lasers typically have a very low divergence beam compared to normal light and therefore can focus to a very small spot on the retina, concentrating the power to a very small area. If the power of a visible laser is high enough, then the blink response of the eye is not sufficient to prevent permanent eye damage. When selecting laser safety goggles for visible lasers it is often a balance between achieving sufficient eye protection, while still allowing some visibility of the laser beam for alignment purposes. For infrared lasers the blink response of the eye provides no protection as the wavelength is normally invisible to the human eye, therefore the power level that laser safety goggles should be worn is less than that for visible lasers.
For details of the Australian and New Zealand laser safety standards and classifications click here
For the US laser safety standards click here
For the European laser safety standards click here