Staging Glaucoma
Chat Highlights
January 29, 2003
Norma Devine, Editor
On Wednesday, January 29, 2003, Dr.
Elliot Werner, a glaucoma specialist at Wills, and the
glaucoma chat group discussed "Staging Glaucoma."
Note: We regret that Internet problems disrupted
the chat. A discussion of staging glaucoma was continued
at a later date. Click here to
read those highlights.
P: Dr. Werner, how
do you define the stages of glaucoma?
Dr. Elliot Werner: Glaucoma
staging is not an exact science. In clinical terms, most
of us use "early," "moderate," "advanced," and "end stage."
These are usually defined by the amount of cupping and field loss
present. For research purposes, more precise definitions
are used.
P: What do you take
into account when staging progression of glaucoma?
Dr. Elliot Werner: Usually
I take into account the amount of visual field loss and the amount
of optic disc tissue that has been lost, then compare the recent
findings to the past findings to determine if progression has
occurred.
P: What about thinning
of the optic nerve?
Dr. Elliot Werner: The
amount of optic disc tissue that has been lost is important.
The optic disc has what is called the disc or neural rim. That
is the actual nerve tissue. As it is lost, it gets thinner in
appearance until it is completely gone. If the rim is thinner
now than before, that is progression.
P: If there is no optic
nerve damage, is that considered a stage of glaucoma?
Dr. Elliot Werner: Technically,
no. In order to diagnose glaucoma there should be some evidence
of damage to the nerve. If there is none, the term "ocular
hypertension" is usually used.
P: Please define each
of the stages, according to the loss of visual field and cupping.
Dr. Elliot Werner: Early
glaucoma is a small visual field defect, such as a paracentral
scotoma. Moderate glaucoma is a more extensive defect, on
only one side of the horizontal midline of the field. Advanced
glaucoma has defects both above and below the horizontal midline.
End stage is profound loss of vision.
P: How much of a change
in the cup-to-disc ratio occurs in early stage glaucoma?
Dr. Elliot Werner: Any
real change in the cup-to-disc ratio would be progression and
damage. It depends where the person starts. A person with a cup-to-disc
ratio of 0.1 who goes to 0.3 would be worse. A person who starts
out life with a ratio of 0.6 and does not change is not progressing.
P: How is the study
of the new Spaeth disc-staging system going?
Dr. Elliot Werner: I'm
not sure. I'm not directly involved in the study. Quite
honestly, the system is a bit complex for most clinicians to use.
It is useful in a research environment.
P: What is disc cupping
and what is normal cupping?
Dr. Elliot Werner: As the
optic disc is damaged in glaucoma, the central portion of the
disc enlarges and gets pushed backwards, so it resembles a cup.
That's why it is called cupping. Normal cup-to-disc ratios
can range from 0.0 to 0.8 in the normal population. It is
the change over time that is important, not the absolute size.
  
Illustrations Copyright 2003 Tim Peters and Company, Inc. Peapack
NJ 07977 USA. All Rights Reserved. www.timpetersandcompany.com
End of highlights for January 29, 2003.
On February 5, Dr. Wilson discussed "Economics of Healthcare"
in the Chat room. Click here for highlights
of that meeting.
Click here for the most recent
glaucoma chat highlights and links to the chat archives.
Click here for
upcoming glaucoma chat events.
|
