Visual discomfort indoors

Abstract

Visual discomfort refers to discomfort or pain in or around the eyes, often associated with headache and/or nausea, and sometimes accompanied by signs such as red, itchy or watering eyes. The lighting conditions likely to cause visual discomfort are insufficient light for the task at hand, dramatic differences in illuminance around the task, shadows, veiling reflections, glare and flicker. To date, research on visual discomfort has been largely reactive, i.e. in response to complaints, but there is now proactive work that explores why discomfort occurs. The hypothesis underlying this work is that the human visual system has evolved to extract information from the natural world efficiently so that when the visual environment departs from the temporal, spatial or chromatic characteristics of the natural world, discomfort is likely because of inefficient neural processing. An important implication is that visual discomfort therefore depends on both the lighting and the décor of a space. Until this approach becomes more established, visual discomfort can be minimised by following carefully developed standards and guidance, by using products that meet appropriate standards, by paying attention to both lighting and décor and by being aware of the wide variation in individual sensitivity.