"what are glassy eyes ? "  (I'm trying to get some opthalmological
info for witness examination in a drunk driving case...Officer says
driver had "glassy eyes" ---what's that mean ?

I would like to take the opportunity to answer this since I found that
this was unanswered.

Glassy eyes can be understood as a fixedly staring and wide-eyed
appearance. Originally, I thought this to mean watery eyes wherein
there seems to be a transparent film covering the eyes, but this was
wrong. It’s just that the eyes are so wide and unblinking that they
simulate a pair of glasses.

Glassy Eyes Confused - Med Help International 
http://www.medhelp.org/perl6/eyecare/archive/422.html
Quote: “People with elevated thyroid levels or Graves' disease may
have a stared or wide-eyed appearance. People using drugs which affect
the central nervous system may also have a glassey eyed look because
they tend to blink less frequently if the drug is actually depressing
the nervous system.”

Glassy eyes is one of the criteria for determining if a person has
been driving drunk. Alcohol depresses the nervous system, and affects
the eyes’ functions, such as size control and blinking. If a person’s
has been found driving with wide eyes that don’t blink, along with
other criteria, that could be a candidate for arrest for substance
abuse.

Search terms used:
"glassy eyes" condition
"glassy eyes" explanation

Other research tools: personal knowledge

I hope this answer has been satisfactory. If you have a problem with
this answer, do please post a request for clarification. Thank you.

Here is pinkfreud-ga's comment to the second version of this question
( http://answers.google.com/answers/main?cmd=threadview&id=190348 ):

Subject: Re: glassy eyes 
From: pinkfreud-ga on 14 Apr 2003 11:31 PDT
    
"Glassy eyes" is a highly subjective term for which I can find no
precise ophthalmological definition. The term generally refers to an
appearance of listlessness in which the eyes are unfocused and without
lustre (which may accompany the dehydration which can result from the
use of alcohol and other drugs.)
 
Here is a thread from a newsgroup that might be of interest to you: 
 
Thread from alt.law-enforcement.traffic newsgroup 
http://groups.google.com/groups?hl=en&lr=lang_en&ie=UTF-8&oe=UTF-8&newwindow=1&safe=off&th=ff4457d6afab1c11&rnum=1

Law enforcement officers have proven to be highly unreliable in
identifying intoxication, even after administering field sobriety
tests. See "DWI/DUI Facts & Fiction" at
http://www2.potsdam.edu/alcohol-info/DrivingIssues/1107196613.html