Definition of reading glass:
(adj) :
of or pertaining to the
root or root cause of the matter;
Thorough going or fundamental
"the spread of the cancer required radical surgery, and the entire organ was removed."
(n) :
person with radical opinions; (Hist. -- 19th-century England) A member of the most progressive wing of the Liberal Party; someone favouring social reform (but generally stopping short of socialism)