Your neck and shoulders should be relaxed, with arms hanging naturally and elbows kept close to the body. The torso may be positioned upright or slightly inclined. Keep at least a 90-degree angle between your trunk and thighs while seated. To avoid upper back and neck strain, keep your monitor in front of you so you don't have to gaze to the left or right. If you spend between three and five hours a day in front of the computer, consider the adjustability of your furniture.
Internet users are at risk for eyestrain from hours spent staring at the computer screen.
To avoid blurred vision, dizziness and headaches that can result from strained vision, keep the computer screen at or below your horizontal line of sight and 18 to 30 inches from your eyes. Occasionally shift your focus to distant objects to relax eye muscles. Glare is a primary cause of eyestrain among computer users. Check for glare with the computer screen turned off, noting if your clothing is reflected on the screen. If you're using a laptop for Internet access, rest it on a stable surface between 26 and 29 inches high to help maintain correct wrist posture.