Can obscure portions of text and render graphic illustrations or photographic images difficult to read. One example is directional lighting that falls onto a person's head or writing hand that creates shadows on horizontal work planes, obscuring reading or writing materials. Overhead cabinets extending over the work surface also create areas of shadow and contrast. When the eyes must continually adjust between different levels of brightness in tasks or surroundings, they work harder and tire faster than in environments where shadows are diffuse and brightness levels relatively uniform. People will sometimes assume awkward positions to avoid a direct glare source or a hot spot on a computer screen, which can result in neck, shoulder or back pain and may lead to repetitive strain injuries.
Overhead glare can contribute to the problem.
Often caused by harsh shadows and high contrast. Interior spaces that are sufficiently illuminated for computer-intensive office or study tasks may still feel dim or gloomy to the people who work in them. Harsh, directional light can make people feel tense and nervous. Good lighting allows people to see what they are doing without physical strain or psychological discomfort. Indirect lighting projects upward, effectively turning the ceiling into a single source of soft, diffuse light, eliminating overhead glare and hot spots on computer screens as well as reflected glare on vertical and horizontal surfaces.