Date of Award


Document Type


Degree Name

Master of Science in Engineering Management


Department of Systems Engineering and Management

First Advisor

Michael E. Miller, PhD


Light in the built environment plays an essential role in the vision and the health of humans through non-visual receptors in the eyes. Unfortunately, image analysts and other Air Force personnel who engage in the detection of objects on softcopy displays are often required to work in very dimly-lit or dark environments as higher illumination reduces the contrast of displayed information. Literature has shown that increases in light exposure improves circadian rhythm entrainment and reduces the negative health consequences of insufficient lighting. This research examines the effects of indoor lighting to determine if increases in ambient illumination or changes to the orientation of light fixtures improves or degrades alertness and visual performance. Positive findings of this study would lead to changes in the environment of image analysts, increasing productivity and long-term health. In a controlled environment, twelve participants were exposed to D65 ambient light at levels of 0, 21, 32, and 43 lux, through overhead lighting, wall-washing, and under-desk illumination orientations. During exposures, participants were asked to visually identify variations in low-contrast Gabor patches on a display. The data was used to calculate the contrast threshold of detectability and response times of participants, thus indicating visual performance. Surveys also measured the subjective alertness and discomfort of participants. Results showed that the orientation of light fixtures significantly affects participant sleepiness, weariness, and discomfort. Additionally, the results indicate that visual detection performance is improved with higher ambient illumination levels employed within this research.

AFIT Designator


DTIC Accession Number