NIGHT-VISION GOGGLE (NVG) VISUAL-ACUITY UNDER IDEAL CONDITIONS WITH VARIOUS ADJUSTMENT PROCEDURES

Night operations involve diverse mission areas and require an increase d reliance on the use of night vision devices, such as night vision go ggles (NVG's). Any reduction in goggle or visual performance which goe s undetected can have a serious effect on flight safety and operationa l capability. Under controlled lighting conditions, a crewmember shoul d be able to obtain the best possible goggle performance, and to deter mine if the goggle is functioning properly. These data represent a sam ple of 218 current USAF aircrew members representing all crew position s in both rotary and fixed-wing aircraft. Three measurements of goggle performance, expressed as NVG visual acuity, were obtained. The first measure, obtained after crewmembers adjusted the goggles with their u sual adjustment methods, showed that they routinely obtain less than o ptimal acuity levels; i.e., averaging between 20/50 and 20/55. The sec ond measure, taken when the NVG Resolution Chart was provided to augme nt their ''usual'' method of adjustment, showed improved performance; i.e., averaging 20/45. The third measure, taken following participatio n in an NVG Adjustment Procedures class, showed the greatest improveme nt, averaging between 20/35 and 20/40. In summary, it is reasonable to conclude that aircrew members who are able to obtain the best possibl e performance for their NVG's under controlled preflight conditions wi ll obtain the best possible goggle performance under the widely varyin g flight conditions.