Effects of Bifocal and Progressive-Addition Corrective Lenses on Aviator Target-Detection Performance.
Interim rept. 1 oct 92-30 Sep 93,
NAVAL AEROSPACE MEDICAL RESEARCH LAB PENSACOLA FL
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The objective of this project was to determine if the type of presbyopic correction worn by aviators, conventional bifocal versus progressive- addition lenses PALs, differentially affects aviator visual search performance. Experienced aviators with tactical fighter aircraft experience searched for high-contrast targets under simulated dawndust lighting conditions while wearing either a standard bifocal ST-25 or PAL spectacle correction. Latency of locating high-contrast targets under these viewing conditions was affected differentially by the type of presbyopic correction used. Specifically, compared to a standard bifocal ST-25, a PAL correction Varilux Infinity significantly lowered the time needed to locate static targets at a cockpit- instrument viewing distance 83 cm. Accuracy of target-location responses was not affected by the type of correction used. In addition, 7 months post experiment, 7 of the 12 participants 58 indicated that they used their PAL correction exclusively when flying the T-39 Sabre Liner. Three subjects 25 used their PAL correction intermittently primarily at night when flying, and two subjects preferred not to use the PALs. These results suggest that a relative to bifocals, speed of responding to static targets at intermediate viewing distances may be improved by wearing PALS and b subjects were able to adapt to PAL lenses quickly in a laboratory setting, using them later in a functional aviation environment.