That assumes an understanding of the cause of the relationship. The
subjects used various programs in their work (not necessarily the same as
web browsers). Could the higher incidence of NTG simply relate to the
subjects constantly changing their focus between the screen and the
enviornment?

The "refractive errors" class was not adequately broken down into
"uses corrective appliance {glasses, contacts}" vs "uncorrected".
In additon, without knowing the distribution of NTG suspects in the study
as a function of refractive error it is impossible to even guess at the
mechanism involved.

In defense of the authors, this was a preliminary study. They are engaged
in a follow-on which should answer some of these questions. I'm also
particularly interested in why being a fat smoker in Japan yields a smaller
chance of being glaucomatic than (what we in the west) call living a
"healthy" lifestyle.
 

Plain and simple....this is a very poorly done study.  It was not done
prospectively, nor was it a randomized trial with controls.
Additionally, myopia is frequently linked with glaucoma, and it does
not sound like careful attention was paid toward a patient's
refractive status.  Not only is myopia quite common in Asian patients,
but the general makeup of glaucoma there is different than in the U.S.
(greater percentage of LTG and narrow angles in Asian patients).  I
personally doubt very seriously that any link will ever be found
between computer use and glaucoma....I've got thousands of office
workers in my practice who use computers all day long and have no
signs of glaucoma.  Likewise, I have plenty of old, suffering glaucoma
patients who virtually never look at a monitor or keyboard.  I'm sure
if this is well-studied here in the U.S. it will be shown to be a
whole lot of bunk.
--Rick Cohn, MD
Glaucoma Specialist
Winter Park, FL