What I /can/ tell you is:

1) Glaucoma is listed as a "Treatment-emergent adverse events
associated with clinical trial participation."  This is very different
from a side effect.  The former does not necessarily imply that the
medicine /caused/ the problem; the latter does.

2) Glaucoma is further listed as "rare" in the preclinical trial of
3,660 subjects used in clinical trials.  "Rare," in this case, is
defined as "less than one in one thousand patients."

So ... in their trial of 3,660 people taking Ambien for some length of
time, one patient reported having glaucoma.  This patient may or may
not have already /had/ glaucoma that was formerly undiagnosed.  That
glaucoma may or may not have been causally associated with the use of
Ambien.

http://www.sanofi-synthelabo.us/products/pi_ambien/pi_ambien.html#ADVERSE_REACTIONS

OR http://www.ambien.com/hcp/pdf/magnum_pi_key.pdf

Hope that helps....

Neil