Apple PowerBook (Duo, 2300 Series) - Manual (Page 137)

External monitor
If you use an external monitor connected to a dock, this suggestion may be
helpful.
m If possible, 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).
Avoiding fatigue
m Change your seated position, stand up, or stretch whenever you start to feel
tired. Frequent short breaks are helpful in reducing fatigue.
m Allow adequate work space so that you can work comfortably. Place papers
or other items so you can view them easily while using your computer. A
document stand may make reading papers more comfortable.
m Eye muscles must work harder to focus on nearby objects. Occasionally
focus your eyes on a distant object, and blink often while you work.
m Clean your screen regularly. Keeping the screen clean helps reduce
unwanted reflections.
What about electromagnetic emissions?
There has been recent public discussion of the possible health effects of
prolonged exposure to extremely low frequency (ELF) and very low
frequency (VLF) electromagnetic fields. Such fields are associated with
electromagnetic sources such as television sets, electrical wiring, and some
household appliances—as well as computer monitors.
Apple has reviewed scientific reports and sought the counsel of government
regulatory agencies and respected health organizations. Based on the
prevailing evidence and opinions, Apple believes that the electric and
magnetic fields produced by computer monitors do not pose a health risk.
In response to those customers who wish to reduce their exposure to
electromagnetic fields, Apple has lowered the emission levels of its products.
130 Appendix A