Advanced Appraisal of Protective Eyewear a Foreseeable Field Capability Published Oct. 11, 2009 By Dr. Jeffrey Wigle 711th Human Performance Wing WRIGHT-PATTERSON AIR FORCE BASE, Ohio -- Air Force Research Laboratory and Physical Optics Corporation took a good look at eyewear worn to prevent laser-related damage and, through their resulting double vision--or rather, DOUBLET (Dual Optical Ultrawide Band Laser Eyewear Transmission) vision--provided field personnel a user-friendly means for assessing the protective capacity of their visors, spectacles, side shields, and similar laser eye protection articles. Designed to facilitate quick analysis by operational units, the self-contained evaluation device is rugged and compact (1.27 ft3 and less than 40 lbs). The capability's highly accurate results ensure compliance with rigorous safety controls governing this critical eyewear, and its moderate cost lowers the expense associated with currently fielded devices. POC developed the new device, a research-quality spectrometer, under Small Business Innovation Research Phase II contract to AFRL. DOUBLET uses a nonscanning (non-laser-based) technology to quantify the optical density of LEP eyewear, a measure that translates into the practical protection level that a given article can be expected to provide. Instead of using a laser, the device employs a tungsten-halogen lamp and a violet diode as its light source. A rugged, powerful, ultramobile personal computer controls the system, performs signal processing, and provides encrypted protection for safe storage of sensitive information--all through a facile touch screen. This straightforward graphical user interface provides step-by-step instructions for taking an OD measurement based on the type of article being examined--glasses versus goggles, for example. DOUBLET's novel measurement method collects the item's complete laser-protection spectrum in as little as 3 sec. The system then compares the collected spectrum to its built-in, predefined design spectrum in order to determine whether the test item meets specifications. Users can elect to receive a simple pass or fail signal of their choosing. The DOUBLET software is also capable of storing and downloading test spectra for future failure analysis, if desired. In addition to ensuring adequate LEP and thus improving aircrew confidence in eyewear performance, the new capability may net substantial cost savings for the Air Force. Existing LEP devices based on other technologies are expensive and, further, are subject to premature replacement (either at the first sign of visible imperfection or according to a generic "mean time between failure" regime that does not consider whether a specific item's protective capacity is in fact compromised). By facilitating regular measurement of LEP items in the hands of the operational units that use them, DOUBLET offers the much more efficient and affordable approach of replacing the eyewear only when it actually fails to meet specifications. This advanced appraisal technology has potential utility in any application--government or commercial--requiring painstaking compliance with exacting LEP safety standards.