Compatibility of the aviation night vision imaging systems and the aging aviator.

With the advent of the night vision goggle (NVG) mission requirements in the United States Army, the reserve components began training with the second generation (AN/PVS-5 & AN/PVS-5A) systems. These systems prohibit the wear of spectacles by the aviator. Certain modifications on some systems allowed for spectacle wear. However, there still exists a 5-h day filter training minimum in which the full NVG with facemask and cushion must be worn without spectacles. The NVG system corrects up to +2.00 diopters of hyperopia and up to -6.00 diopters of myopia, but only +/- 1.00 diopter of astigmatism. A survey of the reserve component (USAR and NG) aviators in the Southwest was conducted to establish the relative incompatibility of the NVG system among an aviator population older than the active component aviators. All medical record custodians received questionnaires and the flight surgeon followed up replies by telephone or on-site visits. We screened a total of 127 aviator records. The aviator's average age was 39.5 years; 65.3% had 20/20 vision and were emmetropes. Of those that wore spectacles, 82.4% had hyperopia or myopia correctable by the built-in optical adjustments contained in the NVG. The other 17.6%, who had vision that exceeded the correction factors built into the NVG, consisted of astigmats with greater than 2.00 diopters of cylinder. Nearly 20% of the aviators who wore corrective lenses exceeded the corrective limits of the goggles that they used. Further, pilots had no specific prescreening instruction. With the development of more sophisticated aviation optics. Three options exist: modify visual standards, allow contact lens wear, or design future systems to be compatible with spectacles.