Polycarbonate Ophthalmic Lenses And Night Vision Goggles In U.S. Army Aviation

Abstract

U.S. Army aviators use the AN/PVS-5 Night Vision Goggles (NVG) with a modified faceplate which enables wearing of corrective spectacles, when required. The next generation NVGs, the Aviator Night Vision Imaging System (ANVIS), permit spectacle wear by design. With only glass lenses available to the aviator requiring optical correction, there is a potential for eye injury from broken glass should the goggles be displaced accidentally. This paper discusses studies conducted at the U.S. Army Aeromedical Research Laboratory, Fort Rucker, Alabama to: (1) compare the impact resistance of glass, CR-39 (plastic), and polycarbonate lenses to simulated NVG tubes, (2) establish the approximate forces necessary to cause glass lens breakage by displaced NVG tubes, and (3) determine the performance of polycarbonate lenses in the aviation environment. Results demonstrate the significant improvement in impact-resistance afforded by polycarbonate ophthalmic lenses, verify the relatively low forces necessary to cause NVG displacement and subsequent glass lens breakage, and establish the feasibility of prescribing polycarbonate lenses for use by aviation personnel.