ABSTRACT
Laser protective eyewear comes in two flavors: full attenuation and alignment eyewear. Full attenuation eyewear will completely block the transmission of a direct exposure laser beam from penetrating the eyewear. Conversely, alignment or partial attenuation allows an individual, while wearing laser eyewear, to have some visibility which means some of the beam's energy will pass through the laser protective eyewear. The Laser Safety Officer is tasked with recommending proper eyewear selection for the wavelength or wavelength region in question to meet the required optical density (OD) for each laser application(s). Once the small source intrabeam OD for each laser wavelength or wavelength region has been posted, various other ancillary conditions emerge which may both positively impact the intended use of the chosen laser protective eyewear. The distinction between OD and visual light transmission (VLT), especially in full attenuation conditions, are sometimes misunderstood or misrepresented. Assumptions abound that a higher OD necessarily implies a reduction of VLT.
