To keep your eye muscles fully flexed, hold out your thumb at arm’s length. Move it in circles, then in figure eights, closer and farther away. Follow it with your eyes. This helps keep the fine motor system of your eyes in working order.
If you keep your eyes fixed for long periods on a computer screen, your eye muscles can temporarily become stuck. To keep your eye muscles loose, look up every ten minutes and focus on a poster located about eight feet away. Then look back at the words on the computer screen. Shift your focus back and forth repeatedly for 30 seconds.