Ocular Discomfort and Other Symptoms of Eyestrain at Low Levels of Illumination.
NIOSH 1975 Mar:44-51
Eyestrain, or asthenopia, a condition arising from the efforts made by individuals to keep their eyes adjusted for seeing, was reviewed and discussed with emphasis on fixation, convergence and control of the size of the pupil. Prescription glasses and training designed to eliminate the symptoms of discomfort and experienced by people when they use their eyes, together with good lighting, were prescribed as remedies for eyestrain. Poor lighting usually results in the deterioration of the eyestrain condition, although the level of luminance that will permit comfort cannot be established with any degree of accuracy. The eye discomfort was found to increase as the day progressed being accompanied by the appearance of headache and fatigue, without refractive errors or changes in amplitude of accommodation, pupil size, phorias and fusional capacity. Frustration and weariness caused by the constant effort to achieve clear vision and coordinate the two eyes were commonly detected, although the role of vision was difficult to pinpoint because of the many factors involved in inducing this condition. Monitoring of the pupil by determining the changes in the diameter of the pupil as a function of the changes in the characteristic luminance area of the visual field, was postulated as an indicator of the discomfort experienced. The authors conclude that the efforts to limit lighting to levels at which some people may not be able to work in comfort are unfortunate and recommend instead the use of lighting levels compatible with satisfactory performance.
Eye-disorders; Lighting-systems; Eye-strain; Physiopathology; Eye-glasses; Eye-protection; Health-hazards; Occupational-health; 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