Apple Macintosh Performa 6400 Series - Manual (Page 152)

You may have to raise your chair so 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 may 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.
m Position the mouse at the same height as your keyboard. Allow adequate
space to use the mouse comfortably.
m Arrange the monitor so the top of the screen is slightly below your eye
level when you’re sitting at the keyboard. The best distance from your eyes
to the screen is up to you, although most people seem to prefer 18 to 28
inches (45 to 70 cm).
m Position the computer to minimize glare and reflections on the screen from
overhead lights and windows.
Thighs horizontal
Shoulders relaxed
Screen positioned to avoid
reflected glare
Forearms and hands
in a straight line
Forearms level
or tilted up slightly
Lower back supported
Feet flat on the floor
Top of the screen at or slightly
below eye level (You may need
to adjust the height of your
monitor by placing something
under it or by raising your
work surface.)
Clearance under work surface
45–70 cm (18–28 in.)
152 Appendix A