When it comes to identifying the risks of an employee developing a computer-related injury, most of the problems revolve around the overuse of computers that result in visual and musculoskeletal problems. Fatigue is also another major complaint that is often dismissed since most employees feel the pressure to work through the condition as opposed to taking steps to prevent the health risks associated with the condition.

In order to respond adequately to complaints, computer operators are ideally encouraged to work closely with health care professionals who can monitor and address eyestrain and headaches. In the case of smaller employers who don't have access to human resource personnel, NIOSH recommends several common-sense tips to combat visual problems. More than anything, the institute points out the need for rest breaks so that computer operators can minimize eyestrain. Even changing focus by glancing away from the screen and looking at an object at least 20 feet away, provides an opportunity to relax the eye muscles.

Another main problem in using computers is that such work often requires sitting relatively motionless for long periods of time with small but repetitive movements of the eyes, head, arms, and fingers, leading to muscle fatigue and eventual muscle injury. Thus, computer users are susceptible to a number of musculoskeletal disorders such as carpal tunnel syndrome and tendonitis. Initial symptoms of the disorders include pain and swelling, numbness and tingling, muscle weakness, and a reduction in range of motion. If these symptoms are not addressed early, they may lead to chronic pain or even permanent disability.

Injury Prevention: Lighting

Fortunately, there are a number of preventive behaviors that can minimize or prevent problems related to using computers, including the use of proper lighting, ergonomic workstations, and the setup of computers.

Lighting should be indirect so it does not directly shine in the operator's eyes and the level of brightness should impede eyestrain in viewing the text and screen but not bright enough to produce glare. There are four basic lighting factors to be monitored:

Quantity–Too often, offices use a combination of artificial lighting and daylight for illumination that can “wash out” images on the screen. Ideally, lighting levels should be somewhat lower when computers are in use (about 28-50 foot-candles as a satisfactory standard).

Contrast–The optimum setting has minimized differences in illumination between the display, the work surface, and the surrounding areas. Diffused lighting is preferable in minimizing hot spots or sources of glare.

Glare–Defined as a bright and comfortable light source, glare may be the result of intensity, angle of source, proximity, or size and tends to annoy or discomfit the user. Glare can result from direct light sources or from reflections off surfaces. Adequate adjustment of lights and well-chosen light sources, as well as careful choice of walls and work surfaces, can limit problems due to glare, both direct and indirect. In addition, shifting work stations around may alleviate glare. Particular care should be taken when work terminals are within 20 feet of windows, unless appropriate window treatment is available. Screen glare filters can minimize glare when they are applied directly to the screen or monitor. There are two available filters–natural density filters, that scatter and diffuse some of the light, and micromesh filters, that both scatter and absorb most of the light with a grid of fibers. These are a last resort as the filters tend to diminish visibility and legibility on the screen itself.

Injury Prevention: Workplace

Work station designs, when conceived properly, can reduce both visual and musculoskeletal discomfort. Design considerations include:

- A comfortable sitting position, with operator able to reach, observe, and use the screen, keyboard, and document

- Proper posture support for the arms, back, legs, and feet

- Adjustable display screens and keyboards

- Computer tables and desks, which are adjustable vertically, to accommodate use of screen and keyboard

- Proper chair height in order to support the lower back

- Document holders to allow for adequate positioning and viewing of material.

In setting up the station, take into consideration the task performed in order to determine if the operator needs to focus more on the printed document or the screen. Chairs are a key factor in preventing back pain and subsequent injury, as well as generally improving performance. The starting point for establishing correct chair height is the distance from the floor to the bend behind the knee. The chair height is adequate when the entire sole of the foot rests on the floor, or footrest, and the back of the knee is slightly higher than the chair seat. In addition, the design of the seat, both size and shape, can be crucial for adequate comfort levels. The seat must be slightly concave and softly padded with the slight angle set for the user's comfort. Armrests should be low and short enough to fit under the work surface so the user may approach the work area closely. Finally, the backrest must support the entire back, including the lower lumbar area.

Lastly, the display screen should be positioned appropriately for the viewer, since operators spend a significant amount of time looking at the display. With the newer computers that have separable and adjustable keyboards and display screens, positioning is more flexible for individual needs. The upper line on the screen should never be higher than the operator's eyes and the screen, and the document holder should be the same distance from the eye in order to stabilize focus. As for the viewing distance, the preferred range is 18-24 inches.

A detachable keyboard is key when adjusting for the operator's comfort and safety. Installing a keyboard extender or tray may offer a lower-than-normal work surface to provide the necessary level of comfort. For most individuals, the optimal working position is attained when the forearms are parallel to the floor with elbows at the side so that the hands may move easily across the keys. The use of a padded or detachable wrist rest may help maintain a straight position for wrist and hands as well.

The mouse position is most functional when the operator's arm is close to the body for support, with a straight line between the hand and forearm. In addition, the upper arm should not be elevated and the top of the wrist should be flat, not angled. A straight wrist may be achieved with a mouse pad or rest.