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Glaucoma Symptoms
Glaucoma is often referred
to as the "silent thief of
sight," because most types
typically cause no pain and
produce no symptoms. For
this reason, glaucoma often
progresses undetected until
the optic nerve already has
been irreversibly damaged,
with varying degrees of
permanent vision loss.
But with acute angle-closure
glaucoma, symptoms that
occur suddenly can include
blurry vision, halos around
lights, intense eye pain,
nausea and vomiting. If you
have these symptoms, make
sure you immediately see an
eye care practitioner or
visit the emergency room so
steps can be taken to
prevent permanent vision
loss.
Diagnosis, Screening and
Tests for Glaucoma
During routine eye exams, a
tonometer is used to measure
your intraocular pressure or
IOP. Your eye typically is
numbed with eye drops, and a
small probe gently rests
against your eye's surface.
Other tonometers direct a
puff of air onto your eye's
surface.
An abnormally high IOP
reading indicates a problem
with the amount of fluid
(aqueous humor) in the eye.
Either the eye is producing
too much fluid, or it's not
draining properly.
Normally, IOP should be
below 21 mmHg (millimeters
of mercury) - a unit of
measurement based on how
much force is exerted within
a certain defined area. If
your IOP is higher than 30
mmHg, your risk of glaucoma
damage is 40 times greater
than someone with an IOP of
15 mmHG or lower.* This is
why glaucoma treatments such
as eye drops are aimed at
keeping IOP low.
Your eye pressure
(intraocular pressure) will
be measured with a
tonometer. Some tonometers
blow a puff of air onto your
eye's surface. Others rest
gently against the surface
of your eye, which will be
numbed with eye drops.
Other methods of monitoring
glaucoma involve imaging of
the eye's optic nerve and
internal structures
(scanning laser polarimetry
or SLP, optical coherence
tomography or OCT, confocal
scanning laser
ophthalmoscopy, etc.) to
establish a baseline and
make sure no obvious changes
have occurred over a period
of time, which might
indicate progressive
glaucoma damage.
Visual field testing is
another way to monitor
whether blind spots are
developing in your range of
vision, resulting from
glaucoma damage to the optic
nerve. Visual field testing
involves staring straight
ahead into a machine and
clicking a button when you
notice a blinking light in
your peripheral vision. The
visual field test may be
repeated at regular
intervals so your eye doctor
can determine the extent of
vision loss.
Instruments such as an
ophthalmoscope also may be
used to help your eye doctor
view internal eye
structures, to make sure
nothing unusual interferes
with the outflow and
drainage of eye fluids.
Ultrasound biomicroscopy
also may be used to evaluate
how well fluids flow through
related angles of the eye's
internal structure.
Specialized lenses also may
be used (gonioscopy) for
better viewing of internal
eye structures.
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