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The
most common form of glaucoma is open-angle glaucoma. In
open-angle glaucoma, the aqueous, or fluid, that normally
flows through the pupil into the anterior chamber (the front
section of the eye's interior) cannot get through the
trabecular meshwork (the eye's filtration area) to the normal
drainage canals. This causes a buildup of pressure in the eye
(intraocular pressure, or IOP), which can damage the optic
nerve and lead to vision loss.
 
Most people who develop open-angle glaucoma notice no
symptoms until vision is impaired.
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In angle-closure glaucoma, the
normal drainage canals are blocked when the area
between the iris and the cornea is not open. This
condition can be chronic (progressing slowly or
occurring persistently) or acute (occurring
suddenly).
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In acute angle-closure glaucoma there is a sudden increase
in intraocular pressure (IOP) due to the buildup of aqueous in
the eye.
Acute angle-closure glaucoma is considered an emergency
because optic nerve damage and subsequent vision loss can
occur within hours of the onset of the problem. Symptoms of
this kind of glaucoma can include nausea and vomiting, seeing
haloes around light, and pain in the eye.
Chronic angle-closure glaucoma, like open-angle
glaucoma, may cause vision damage without symptoms.
Although angle-closure glaucoma is unusual, people of Asian
or Eskimo ancestry are at higher risk of developing it. As
with other forms of glaucoma, age and family history are also
risk factors, and the problem seems to occur in older women
more often than others.
Both open-angle and angle-closure glaucoma can be primary or
secondary. A primary condition is one that
cannot be attributed to any known cause. A secondary condition
can be traced to another cause, such as previous injury or
illness.
"Normal (or low) tension" glaucoma is an
unusual and poorly understood form of the disease. In this
type of glaucoma, the optic nerve is damaged even though the
patient's intraocular pressure is consistently within a range
usually considered normal.
Childhood glaucoma is rare, and starts in infancy,
childhood or adolescence. Like open-angle glaucoma, there are
few, if any, symptoms in the early stage, and blindness can
result if it is left untreated. Like most types of glaucoma,
this type of glaucoma is thought to have a hereditary
component.
Congenital glaucoma is a type of childhood glaucoma
that usually appears soon after birth, although it can become
apparent later in the first year of life. Unlike other
childhood glaucomas, congenital glaucoma often has noticeable
signs, including tearing, light sensitivity, and cloudiness of
the cornea. This type of glaucoma is more common in boys, and
can affect one or both eyes.
Your ophthalmologist may tell you that you're a glaucoma
suspect if you have one or more risk factors for glaucoma.
These may include elevated intraocular pressure (IOP), family
history, ethnic background, older age, optic nerve appearance,
and other factors.
Elevated IOP is sometimes called ocular hypertension.
This means that your IOP is higher than what is considered
"normal." A diagnosis of ocular hypertension does
not mean you have glaucoma, but it does mean you're at
increased risk, and should probably have frequent medical eye
examinations. Sometimes your ophthalmologist will recommend
medication to lower your IOP.
Treatment for glaucoma may include medication and/or surgery.
If you think you're at risk for glaucoma, and haven't had a
medical eye examination in the past two years, you can call
the Glaucoma 2001 Referral Line, 1-800-391-EYES (3937)
for a referral to an ophthalmologist in your area. If you have
no medical insurance and are unable to pay for care, the
initial examination, and subsequent medical care for glaucoma,
are at no cost to you.
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