Dynamic Visual Acuity Assessment Through Visors

Abstract : This study was undertaken to determine the utility of a dynamic visual acuity assessment methodology for examining the effects of looking through a transparent component on visual performance. The different types of transparent components that can be investigated using this methodology include, but are not limited to, night vision goggles, tinted visors, laser eye protection spectacles, and aircraft windscreens. Transparency attributes that can be investigated include transmission coefficient, reflection coefficient, glare, light level, target contrast, target type, resolution, spectral transmission, haze, scratches, and distortion. The visual task may be a target detection or a target recognition type of task, performed with or without search. The methodology used in this study consists of smoothly and continuously decreasing the distance between the observer and a visual test target, until the observer can accurately perform the required visual task. In this study, the observer was required to visually search and detect a circular black dot in a quadrant, while viewing through a tinted visor. The lighting conditions were not at a level for which the tinted visor was intended to be used, so it was expected that the visor would reduce visual acuity instead of aiding visual performance, as it normally would be expected to do. The objective of the study was to determine the 95% reproducibility limit for the methodology. This limit was found to be on the order of 10% to 15%, which is quite good for an assessment of this type that involves human observers performing a visual task over an extended period. The methodology appears to be viable.