Simulated night vision goggle wear and colored aftereffects.

Background: Surveys of military pilots report that between 1.6% and 65% of the respondents experienced altered color vision after night vision goggle (NVG) wear. For the majority of these pilots, the aftereffect was a brownish afterimage that lasted less than 10 min. Given the large disparity in the surveys, we asked subjects to wear goggles which simulated NVGs to determine the nature and duration of any color aftereffects after removing the goggles.

Methods: Two separate experiments were conducted after wearing the goggles for 30 continuous minutes. The first measured the adaptation effects on color appearance by determining the spectral locations of unique blue and unique yellow. The second measured the adaptation effects on color discrimination using the Lanthony Desaturated D15 (Desat D15) color vision test.

Results: The location of unique blue shifted to a longer wavelength by 4 nm immediately after removing the goggles and returned to baseline by 12 min post-wear. The unique yellow location was unaffected by the color aftereffect. In the second experiment, the time to complete the Desat D15 was 13% longer than baseline for the first 6 min post-wear. There was also a decrease in the frequency of errors relative to baseline. Only one subject reported an afterimage in either experiment.

Conclusions: The results showed that the color aftereffects were subtle and unlikely to cause major color vision problems. The time course of the color aftereffect in this experiment resembled short-term adaptation effects.