Because most lighting and the windows in buildings have not been designed for computer users, they produce glare, which is bad enough in general, but unhealthy for people who view computer screens. When people cannot see their computer screens properly because of glare, they tend to crane their necks, causing strain on the spine and muscle spasms. It also strains vision and causes headaches.
A common remedy is a screen with a non-glare surface or a filter fitted over the screen. In offices or computer rooms where management does not care sufficiently about comfort and health of occupants, people often erect makeshift shades or canopies of cardboard (usually the same places where CRT displays rest on telephone directories to place them at the correct height).
Glare Prevention
These are just remedies. A better strategy is prevention.
Construction firms equip most office and similar buildings with what is called 'base building' lighting. This is usually the cheapest form of fluorescent lighting giving stark white illumination with only a minimum of baffling or lenses to diffuse the light.
The best lighting mimics a slightly overcast day. It eliminates the hard-edged shadows that are evidence of bad lighting.
That can be achieved in a building using indirect lighting. The light fitting is suspended from the ceiling with a reflector beneath the fluorescent tubes so that the light bounces off the ceiling. This spreads the light more evenly.
The reflector can shed a soft-edged shadow below the light fitting and create a gloomy appearance. To avoid this, many fittings combine direct and indirect lighting. A reflector bounces light up and directs it down through an aperture with baffles. In some, the downlight is via a decorative pattern of holes or slots.
The downlight increases illumination on working surfaces. The indirect light eliminates glare and sharp changes in contrast.
Desk Lighting
Devices are also available to provide indirect light at certain parts of a floor or at individual workstations (see illustrations). In one type, the light fitting is mounted on a pole and above it is a reflector. In workstations, reflectors or canopies are mounted on the partitions or panels.
For best visual comfort, people require individual control of their lighting, which can be achieved with the direct and indirect lighting at workstations. Many offices provide task lights fitted under shelves or attached to panels, or table lamps that people can switch on to read documents and switch off when they are viewing the screen.
Harnessing Sunlight
Sunlight can be a major problem. Blinds are an obvious solution, but they can cause disputes among the people in the space. When blinds are pulled down for comfort of people close to the windows, they block the outside view for everybody. Research has shown that outside views help morale.
Another solution is a device called a lightshelf, which both blocks direct sunlight and directs it into the floor space by bouncing it off the ceiling, turning sunlight into indirect light. Lightshelves and external sunshades can be retrofitted to existing buildings.
Glare is just one aspect of bad lighting. Others are hard shadows and sudden changes in contrast. To overcome them, the base-building lighting should be upgraded with indirect or direct/indirect lighting, and individual areas and workstations can be fitted with their own direct/indirect-lighting fittings.
For further reading:
A Means of Saving Lighting Costs
Desks for Comfortable Computer Use
Sources: BC Hydro, National Research Council of Canada (NRCC)
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