Apple MB535LL User Guide - Page 80

 Do not write on the screen or touch the screen with a sharp object.  If you will not be using your display and computer for a day or more, turn off the computer and display or use Energy Saver.  Turn off your display, turn down the brightness, or use a screen saver program that dims or varies the image on the screen when the computer is idle for a prolonged time. Important Ergonomic and Health-Related Information Here are some guidelines for adjusting the furniture in your office to reduce glare and to accommodate your physical size and shape.  Use an adjustable chair that provides firm, comfortable support. Adjust the height of the chair so your thighs are tilted slightly and your feet are flat on the floor. The back of the chair should support your lower back (lumbar region). Follow the manufacturer's instructions for adjusting the backrest to fit your body properly.  When you use the computer keyboard, your shoulders should be relaxed. Your upper arm and forearm should form an approximate right angle, with your wrist and hand in roughly a straight line. You may have to raise the chair so that your forearms and hands are at the proper angle to the keyboard. If this makes it impossible to rest your feet flat on the floor, you can use a footrest with adjustable height and tilt to make up for any gap between the floor and your feet. Or you can lower the desktop to eliminate the need for a footrest. Another option is to use a desk with a keyboard tray that's lower than the regular work surface. 80 Appendix B Safety, Maintenance, and Ergonomics