Page 114 - LASERS & IPLS IN MEDICAL/AESTHETIC APPLICATIONS

Chapter 1 – Fundamentals of Medical/Aesthetic Lasers and IPLs v1.1
Hence, a pair of laser safety glasses designed to protect the wearer from the output from a continuous Nd:YAG laser at 1064 nm with a maximum power output of 50 Watts in a 5 mm spot diameter. This equates to a maximum power density on the skin/eyes of 2.55 million Watts/cm2. From the EN 207:2017 tables, this power density falls between scale numbers L5 and L6. In this situation, we would choose the L6 scale number as the lowest number required to ensure safe use of these glasses.
So, in this case, the full safety specification for this 50W Nd:YAG laser is D 1064 L6 where:
D – continuous beam
1064 nm – laser wavelength
L6 – the EN 207:2017 scale number for eyewear up to 107 W/cm2
In this situation, the scale number relates to the optical density of 6. See figure 62 for some real-world examples in a real clinic.
Laser eyewear must meet the requirements of EN 207:2017 and be marked with:
• The wavelength or wavelength range (in nanometres) for which protection is valid
• The test conditions as a combination of letters D,I,R and M (specifying continuous
wave, D, or a variety of pulse conditions, I, R and M)
• The filter scale number in the form LBn where ‘n’ is an integer (lowest scale number,
if protection over the required wavelength range). Note that the ‘scale number’ also
indicates the minimum optical density for that wavelength range.
• The manufacturer’s identification mark, if required.
The following are good sources of laser safety information:
1. BS EN 60825-1: 2014. Safety of laser products: Part 1. Equipment classification and requirements
2. PD IEC TR 60825-14:2004. Safety of laser products - Part 14: A user’s guide. British Standards Institution
3. BS EN207:2017. Personal eye-protection equipment - Filters and eyeprotectors against laser radiation (laser eye-protectors)
4. Federal Performance Standard for Laser Products, 21 CFR 1040.10, Center for Devices and Radiological Health, Rockville, Maryland
5. General Product Safety Regulations 2005, Statutory Instrument 2005 No. 1803, OPSI
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Chapter 1 LEVEL A Fundamentals of Lasers/IPLs
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