Glaucoma is a group of eye disorders in which damage to the
optic nerve causes some vision loss. There are three basic types of
Open-angle glaucoma (OAG) is the
most common type of glaucoma. In open-angle glaucoma, slow damage to the nerve
in the back of the eye (optic nerve) causes gradual loss of eyesight. At first,
the person loses side or outer (peripheral) vision. If open-angle glaucoma is
not treated, vision loss continues until total blindness develops.
Below are common symptoms associated with each eye problem.
Nearsightedness: Blurred vision that's worse when you are looking at distant objects suggests that you may be nearsighted, or myopic. People with myopia often have very good near vision.
Farsightedness: Blurred vision that's present when you are looking at near objects or, more commonly, near and far objects indicates that you may be farsighted, or hyperopic.
Astigmatism: Blurry vision can occur at any distance and usually...
This type of glaucoma can occur in both eyes at the same time. However,
often one eye is more severely affected than the other. Sometimes much of the
person's eyesight is affected before the condition is noticed.
Open-angle glaucoma has been called simple
glaucoma, chronic glaucoma, and wide-angle glaucoma.
with open-angle glaucoma have higher-than-normal pressure in their eyes.
But some people with open-angle glaucoma have normal pressure in their
eyes. This type is called low-tension or normal-tension glaucoma.
Closed-angle glaucoma (CAG)
may cause sudden blurred vision with pain and redness, usually in one eye
first. In closed-angle glaucoma, the colored part of the eye (iris) and the
lens block the movement of fluid between the chambers of the eye. The blockage
of fluid causes pressure to build and makes the iris press on the drainage
system (trabecular meshwork) of the eye. The increased pressure can cause
damage to the optic nerve, leading to vision loss and possible blindness. It is
also sometimes referred to as primary angle-closure glaucoma (PACG).
Closed-angle glaucoma may cause sudden blurred vision with
pain and redness, usually in one eye first. See a picture of possible
areas of pain associated with CAG.
One type of closed-angle glaucoma (acute
closed-angle glaucoma) can be an emergency situation and usually needs
immediate medical care to prevent permanent damage to the affected eye. The
opposite eye is also usually examined and eventually treated because the
condition could affect the other eye in the future.
develop a form of closed-angle glaucoma called subacute angle-closure glaucoma.
If you have this form of glaucoma, you have brief episodes of symptoms that
develop and then go away on their own without treatment. But over time these
episodes damage your eyesight and the drainage system in your
Closed-angle glaucoma can also become a long-term problem
(chronic angle-closure glaucoma). Chronic closed-angle glaucoma develops slowly
Congenital glaucoma is a rare
form of glaucoma that is present in babies at birth. It is often caused by a
birth defect that can cause abnormal development of structures in the eye. Some
birth defects may develop because of an inherited condition, such as
Congenital glaucoma is usually diagnosed by the
end of the first year of life. About one-half of these children are diagnosed
Congenital glaucoma must be treated as soon as possible
to avoid loss of eyesight or blindness.
Glaucoma that develops between birth and age 3 is called
People between the ages of 3 and young
adulthood can develop another type of developmental glaucoma called juvenile
Glaucoma can also be classified as:
Primary glaucoma. Primary glaucoma refers to glaucoma
that is not caused by another eye or medical condition.
Secondary glaucoma. Secondary glaucoma refers to
glaucoma that develops as a result of another condition.
Secondary glaucoma may develop as a result of
eye injury or eye tumors or after eye surgery.
can develop as a complication of a disease, such as diabetes. Diabetes can
cause new blood vessels to grow into the
drainage angle of the eye (trabecular meshwork) and
create scarring. This scarring can limit drainage of the fluid (aqueous humor)
out of the eye. This blood vessel problem is called neovascular
Certain medicines (corticosteroids) may cause secondary
glaucoma when they are used to treat eye inflammation and other diseases. They
unintentionally cause a rise in pressure within the eye.
may develop as a result of the breakdown and flaking off of the coloring
(pigment) found in the iris and the part of the eye that produces fluid
(ciliary body). These flakes of pigment block the fluid drainage system of the
eye. This type of secondary glaucoma is called pigmentary
Another type of common secondary glaucoma can occur when
a different type of flaky material is produced in the eye. The origin of this
white, flaky material is not clearly known, but it can block the fluid drainage
system of the eye. This type of secondary glaucoma is called pseudoexfoliation
glaucoma or exfoliation syndrome.
A set of diseases called the ICE
syndrome affect the iris and cornea and can cause glaucoma.
Doctors classify glaucoma according to the
severity of the disease.1
Ocular hypertension. Consistently elevated pressure
inside the eye (greater than 21 millimeters of mercury [mm Hg]) without any
evidence of damage to the optic nerve or loss of visual field is called ocular
hypertension. Some people with ocular hypertension may still need treatment if
the pressure in the eye is high enough to pose a risk of damaging the optic
nerve over the long term.
Mild glaucoma. Mild glaucoma refers to optic nerve
damage with a normal visual field or minimal loss of outer (peripheral) vision.
If there are signs of optic nerve damage without visual loss, the person may be
considered as possibly having glaucoma (a glaucoma suspect).
Moderate glaucoma. Moderate glaucoma refers to optic
nerve damage with moderate loss of vision in at least one eye. However, sight
in the center of the eye (central vision) is not affected in moderate
Severe glaucoma. Severe glaucoma refers to optic
nerve damage with loss of vision in both eyes or loss of sight in one eye that
includes central vision loss.
American Academy of Ophthalmology (2005).
Primary Open-Angle Glaucoma, Limited Revision (Preferred Practice Pattern). San Francisco: American Academy of Ophthalmology.
Also available online: http://www.aao.org/ppp.
Primary Medical Reviewer
Kathleen Romito, MD - Family Medicine
Specialist Medical Reviewer
Christopher J. Rudnisky, MD, MPH, FRCSC - Ophthalmology
May 5, 2010
WebMD Medical Reference from Healthwise
May 05, 2010
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