Are you working with laser beams, or laser devices? According to the Canadian Standards Association, section z94.3.1-09, there are special considerations with regard to the safety of your eyes and laser light.
The class of the laser (which is determined by its power) determines if laser safety eyewear is needed. Class I and II lasers are quite safe, and do not require any safety eyewear, since the eye’s natural defenses will protect against damaging levels of exposure. (However, they should still be used responsibly, and we suggest you watch the video to which we refer at the end of this blog post!)
Class IIIa, IIIb and IV lasers DO require safety glasses to protect against both direct and scattered radiation.
Choosing Laser Safety Eyewear
Laser safety eyewear works by both absorption and reflection. Light is absorbed through mineral glass or organic dyes. Light is reflected through the use of holograms and dielectric coatings embedded into the lens substrate. The key to choosing laser safety eyewear is to carefully match what the laser is emitting to what the eyewear is able to protect.
- Since laser light usually operates on a single wavelength, safety eyewear must correspond to that wavelength. For an interesting demonstration on this, have a look at the following laser eye protection demonstration video:
- The O.D. (optical density, i.e. the degree to which the lens slows the light rays) of the eyewear must be sufficient to reduce the laser light below the maximum permissible exposure levels.
And of course, due to the fine nature of laser light, fit and comfort of the eyewear are critical to ensure maximum benefit.
Other Special Considerations
According to the CSA, there are some other special considerations regarding laser-protective eyewear:
- Users should be cognizant that the filters within laser-protective eyewear are in good condition over time, as exposure to laser light will gradually reduce their efficacy.
- Carbon dioxide lasers (CO2) lasers required special CO2 eyewear.
- If the laser is “pulsed” be sure to tell your Optometrist the energy level (joules), pulse duration (seconds) and rep rate (hertz).
A Final Warning
We strongly recommend you refer to CSA z94.3.1-09 for full standards regarding the use of laser safety eyewear.
Since lasers have been in the news a lot over the last few years (being misused by pranksters who are pointing them at airplanes and animals), we also would like to refer you to a fun video….it’s a spoof on “Dumb Ways to Die” called “Dumb Ways to Blind”. CLICK HERE to view.
And remember, always be “Eye safe”!