There must be good colour and contrast conditions without too great luminance variation within the field of vision, having regard to the nature of the work and the employees’ eyesight.Workplaces must be designed so as to avoid disturbing reflective light or contrast glare that can impede work at computer screens, machinery, instruments readings etc. by coordinating the design of the workplace and work station with the positioning and technical characteristics of the artificial light sources. Light sources such as windows and other openings, transparent or translucent walls and light-coloured equipment and walls must not cause direct glare and cause as little reflection as possible.Windows must be fitted with adequate adjustable screening devices to reduce daylight penetration to workplaces with computer screens.