According to the American Optometric Association, 46 percent of Americans spend at least five hours a day on a computer or smartphone. When looking at a screen, many people hold their head forward of center and slouch, which puts many upper-body muscles in a shortened position.Here are some ways to avoid pain and strain: Computer users tend to blink very little and stare straight ahead, not using their peripheral vision. Be sure to keep blinking, which washes your eyes in naturally therapeutic tears and breaks up your stare. Take frequent rest breaks using the 20-20 Rule: every 20 minutes, spend 20 seconds looking at something far away, preferably gazing out a window. Also, stand up and move as much a possible. This is a great time to do eye-muscle stretches and range-of-motion exercises for your back and neck. Use your fingertips to gently massage around your eyes, temples, and forehead. Finally, rub your palms together and gently cup your closed eyes. Relax and breathe freely. Make sure you have good light, and check that your monitor is the correct distance away from your eyes and at the right height. Also, adjust the screen settings to where they are comfortable in terms of resolution and flicker. If you wear eyeglasses, have them checked. For example, in order for some people to see clearly with their heads held in an upright and balanced position, and without chronic tightness in the back of the neck, they may need to have a prescription for a longer focal length or larger bifocal inserts, or have an adjustment of their eyeglass frames if they are bent or twisted. Some people may need a stronger or weaker prescription. If your doctor has prescribed a pair of glasses specifically for seeing the computer screen, wear them.Mary Betts Sinclair is an Oregon-based educator and bodyworker. Learn more about her at www.marybettssinclair.com.