Laser Eye Protection PDF

# LASER EYE PROTECTION 1. A vendor will want to know the details of the exposure conditions you are working in before selling you a pair of safety glasses. You will need to be able to tell the vendor whether you are interested in protection from momentary accidental direct exposure to a laser beam,...

# LASER EYE PROTECTION 1. A vendor will want to know the details of the exposure conditions you are working in before selling you a pair of safety glasses. You will need to be able to tell the vendor whether you are interested in protection from momentary accidental direct exposure to a laser beam, or from diffuse reflections for an extended period of time. 5. Another consideration when selecting safety glasses is the transmittance of the eyewear for a particular wavelength, which is known as its optical density (OD). To offer adequate protection, eyewear must have the appropriate OD. Laser safety standards in the US and Europe allow vendors to calculate the OD that your eyewear requires based on the exposure limits of your specific application. 10. (...) Vendors also offer a selection of glasses that allow you to see enough of the beam to align it. In some instances, though, it is better to use a low-power laser for alignment rather than relying on safety eyewear. 15. Crucially, your eyewear must provide a high transmission in the visible range so that you can see what you are doing. Be aware that if the eyewear has a high OD in the near-infrared it may also be very effective at blocking red light and consequently any warning lights on your equipment. 20. The lenses in eyewear are made from either glass of polycarbonate filters. Glass filters are typically more expensive but give better protection (owing to their greater OD) and better colour recognition. Bear in mind that safety eyewear only filters a specific range of wavelengths. If you are using a tunable laser, such as an optical parametric oscillator, make sure that you mention all applicable wavelengths to the vendor. It may be necessary to buy several pairs of glasses to cover broadband filters that can deal with multiwavelength sources. 25. If you know that you will be wearing the eyewear for an extended period of time, comfort is also an issue. A large choice of frames is available, but be careful to choose a style that protects against stray beams entering the eye. All eyewear comes with the wavelength range it blocks, etched onto the lenses or the arm of the glasses. adapted from OLE, March 2003