Individual differences in contrast sensitivity.
NIOSH 1975 Mar:62-72
Studies were carried out in 156 subjects aged 20 to 70 years, to determine the contrast sensitivity as a function of luminance. Contrast sensitivity curves were established for background luminance ranging from 0.001 to 500 footlamberts for a 4 minute disc in continuous exposures of 0.20 seconds each, in the center of four adjustable fixation lights. The test subject was instructed to adjust the luminance to achieve a detection threshold, until he could barely perceive that a light was there. The data obtained were classified as a function of age, in groups of 10 year age spans, and used to study lighting standard problems. The curve obtained for the 20 to 30 year old group was used as the standard visibility reference to compare the contrast sensitivity of the various age groups. Individual differences in visibility levels were evident when used in context with the prevailing United States lighting standards. Individuals in the 20 to 30 year age group had the highest sensitivity and those in the 60 to 70 year group had the lowest. The 60 to 70 year old group required 2.51 times the contrast to see as well as the 20 to 30 year old group. The author concludes that the technique used gives the best estimate of the effect introduced by a change in the effective visibility level criterion of a given population.
Age-factors; Lighting-systems; Eye-function-tests; Visual-perception; Illumination; Standards; Eyesight
The Occupational Safety and Health Effects Associated with Reduced Levels of Illumination. Proceedings of a Symposium, July 11-12, 1974, Cincinnati, Ohio, NIOSH, Division of Laboratory and Criteria Development, HEW Publication No. (NIOSH) 75-142