Eyestrain relief possible on ubuntu?

[Erik Christiansen]

Distribution: Ubuntu 5.10

The glare of the white background in the GUI applications make my eyes
very sore after a few hours. (Fortunately I can spend most of my 8 hrs
per day in xterms with yellow on darkslategrey.)

The man pages for x-session-manager (aka gnome-session) and gdm haven't
helped. Nor have the HowTos on the ubuntu site. Some googling came up
with http://art.gnome.org/screenshots/gnome214/59 , which shows a
marvellous yellow-bordered grey background gnome application theme, but
how to obtain one?

Salvation seemed to be at hand at:
http://www.gnome.org/learn/access-guide/2.8/ch04s02.html , but ubuntu
appears to lack the vital menu option:

Applications->Desktop_Preferences

Checking (a little belatedly) the "Help Topics", 4.2.2 also advocates:

Applications->Desktop_Preferences->Theme

Now, if it's in the Help, how come it's missing from the desktop?
(Including Applications->System_Tools->Applications_Menu_Editor, and 
Applications->Add_Applications)

Erik