Posture

Your posture is probably the most important thing to be aware of. Your body is the best indicator of the strain of sitting at a computer. Taking the time to position your computer and establish your comfort level will reduce stress to your spine, lower back and shoulders. Below is a list of recommendations. Remember to consider your capabilities when reviewing this list; some of the points are not are applicable to persons with accessibility issues.

• Monitor 20-26" from eyes
• Top of monitor no higher than 0 degrees
• Center of monitor at 15 degrees
• Bottom of monitor no lower than 40 degrees
• Elbow parallel to middle of keyboard
• Lumbar region of the spine: inward curve
• Thorax: outward curve
• Eyes parallel with top of monitor
• Forearm parallel to floor
• Wrists straight
• Chair swivels so operator can move periodically
  

Furniture

In setting up a comfortable computing environment--a workstation-- three basic items should be considered. This includes a chair, desk and lighting. Adjusting these features to your comfort level can reduce the need for added furniture.

Chair

The chair is one of the most important parts of the workstation; therefore, a properly designed adjusted chair, along with appropriate posture, is important to help reduce or prevent back stress, restricted circulation, irritation and fatigue, and other distractions caused by the discomfort of an inappropriate posture. Remember, you may not always realize that your discomfort could be a result of inappropriate posture, and you may add to the problem by constantly trying to adjust your seating position to remain comfortable. Your chair should promote proper working posture and avoid pressure on sensitive parts of the body. You should have the chair adjusted to where:

• Your feet are flat on the floor, with knees at an angle of 90 degrees or slightly more. If the chair is too high, pressure under the thighs reduces circulation to the lower legs. Sitting in a chair that is too low can result in lower back pain.
• The chair's backrest supports the natural inward curve of the lumbar area, or lower spine. The backrest should either be small enough to fit into the small of the back, clearing the pelvis and back of the rib cage (thoracic region), or curved to provide adequate support. Inadequate lumbar support places excess pressure on the spine.
• The backrest angle is set so that your hip-torso angle is 90 degrees or slightly greater. Leaning forward too much compresses the internal organs and disks of the back. Many people prefer to lean back slightly while working at a computer. Don't lean back too far, though, or you'll have to extend your arms too much to reach the keyboard and flex your neck forward to see the monitor.
• If your chair has a back rest that moves back and forth with you, adjust the back rest tension to give adequate support to your weight.
• Back of the knees are 2-3 inches forward of the chairs front edge. This eliminates any pressure in the popliteal area (back of the knee) which contains blood vessels and nerves. Excessive pressure in this area should be avoided. Some backrests adjust to effectively shorten the seat pan. If enough popliteal clearance does not exist and the chair does not adjust, then another chair with a shorter seat pan should be acquired.
• Where arm-rests are used, elbows and lower arms should rest lightly so as not to cause circulatory or nerve problems. Shoulders need to be relaxed, not hunched up. Arms should be close to the body and not required to make frequent, far reaches or be held away from the body. This can occur if the chair has arm-rests that do not allow the worker to sit in close to the table. Arm-rests can also get in the way if they are too high for the user. Where problems occur, lower or remove the armrests, or obtain a different chair.
• Change your position occasionally during the day by raising or lowering your chair a little, adjusting the back angle slightly or "unlocking" the back-rest, if possible, to let it move with you.

Note: The seat and back-rest should support a comfortable posture that permits frequent variations in the sitting position through slight body shifts and/or chair adjustments. 

Desk

Worksurface height should be appropriate for the type of work being performed, and to your dimensions. This is usually determined by your standing or seated elbow heights. Most work surfaces are horizontal, which is preferred for writing and many other daily activities. However, where poor postures are noticed, such as leaning over a table to read documents, it may be advantageous to tilt the work surface towards you. This will reduce stressful, static postures of the torso and neck. An example would be a drafting table. Frequently used items such as keyboards, telephones, calculators, etc., are recommended to be within easy reach so as to avoid the need for stressful postures(Optimal distance 14-16 inches).Leg space needs to be adequate for the worker and clear of obstacles.

Lighting

Ceiling suspended indirect lighting. Control outside light with blinds and shades. Keep ambient light levels low and supplement with task lighting.In a computing environment of any size, the best solution to avoid glare and reflections on the screen, as well as for overall visual performance, is ceiling suspended, indirect lighting. Wall mounted lamps may also be appropriate in certain instances, because some tasks and individuals require more light than others. First we have to understand what we are trying to accomplish. When evaluating a monitor, high contrast is desirable. You want the letters to stand out from the background. Anti-glare screens have been effective in certain instances, but should be evaluated before purchase. Some anti-glare screens reduce glare by 99%, but even that may not be enough for a very bright lighting. Remember, because the front of the screen is glass, something is going to be reflected from it. The goal is to reduce the contrast in those reflections.