Protective Eyewear
Laser work and similar operations create intense concentrations of heat, ultraviolet, infrared and reflected light radiation. A laser beam of sufficient power, can produce intensities greater than those experienced when looking directly at the sun. Unprotected laser exposure may result in eye injuries including retinal burns, cataracts and permanent blindness. When lasers produce invisible ultraviolet or other radiation, both employees and visitors should use appropriate eye protection at all times.
Lasers should be mounted so that the beam path is not at eye level for standing or seated individuals. Laser protective eyewear of adequate optical density and threshold limit for the beam(s) under manipulation must be provided and worn whenever laser exposure could exceed the Maximum Permissible Exposure (MPE). Procedures and practices must ensure that optical systems and power levels are not adjusted upstream during critical open beam operations, such as beam alignment. The need for laser eye protection must be balanced by the need for adequate visible light transmission. Eye protection is required when working with Class 3b and 4 lasers, and recommended for other classes where feasible. It is the responsibility of the clinical manager to obtain appropriate laser protective eyewear.
To select appropriate eye protection, the user needs to know the wavelength of the laser and the optical density required. Eyewear must be appropriate for the wavelength of the laser used. For example, laser eye protection for a green laser will offer little or no protection for a red laser. Optical density is the measure of how much laser radiation is allowed to pass through and is just as important as wavelength. Just because your safety glasses are the right color does not mean it will stop the laser.
For assistance in selecting laser eye protection, contact the Laser Safety Officer (LSO) at ehrs@drexel.edu. The LSO can assist the user in determining the proper parameters of such eyewear, and can provide contact numbers for vendors. Laser eye protection must be inspected prior to use and also periodically, to ensure that it is in good condition. There are online sources available where the appropriate optical density is calculated for you. Always consult the LSO to confirm these results. Always err on the side of caution and round up the optical density required.
All protective equipment must be permanently labeled with the optical density and wavelength(s) for which protection is afforded.