The assessment of lighting conditions at work must include not only the light intensity but also other characteristics, such as shadows, contrasts and colour. The desirable quantity of light depends on the fineness of the detail and the accuracy required in performance of the task. With regard to the quality of light, many complex factors are involved such as glare, diffusion of light, direction, uniformity and distribution. Dim light associated with high visual demands may lead to eye strain and fatigue. Exposure to the dim light of inadequate illuminated work-places or to the partial darkness of a mine or a darkroom for eight hours a day over a long time, can cause both acute and chronic effects on health. Dim work-places cause headache, eye pain, lachrymation and congestion around the cornea, particularly associated with eye strain from trying to see small objects. Dark work-places cause miner's nystagmus. Distraction from visual tasks and loss of concentration may result from direct glare. This kind of glare is also associated with discomfort, annoyance, and visual fatigue. Intense direct glare may also result in temporary loss of visual ability, as in the case of drivers exposed to direct intense light from on-coming cars at night. Other kinds of glare include the indirect glare from an intense light spot which may cause blurring of vision. Reflected glare from shiny surfaces or dials can obscure details and prevent perception of visual displays. In the occupational environment, intense colours may result in fatigue of certain retinal cones.
The Encyclopedia of World Problems and Human Potential is a collaboration between UIA and Mankind 2000, started in 1972. It is the result of an ambitious effort to collect and present information on the problems with which humanity is confronted, as well as the challenges such problems pose to concept formation, values and development strategies. Problems included are those identified in international periodicals but especially in the documents of some 60,000 international non-profit organizations, profiled in the Yearbook of International Organizations.
The Encyclopedia includes problems which such groups choose to perceive and act upon, whether or not their existence is denied by others claiming greater expertise. Indeed such claims and counter-claims figure in many of the problem descriptions in order to reflect the often paralyzing dynamics of international debate. In the light of the interdependence demonstrated among world problems in every sector, emphasis is placed on the need for approaches which are sufficiently complex to encompass the factions, conflicts and rival worldviews that undermine collective initiative towards a promising future.
Non-profit, apolitical, independent, and non-governmental in nature, the UIA has been a pioneer in the research, monitoring and provision of information on international organizations, international associations and their global challenges since 1907.