Glaucoma is
a medical condition in which loss of vision (eyesight) can result from
excessively high pressure in the eyeball. (Pressure within the eye
is measured using a technique called
oculoplethysmography which is important for detecting the possibility
of glaucoma.)
Glaucoma is classified as either: |
Primary Glaucoma |
Primary Glaucoma refers to high pressure in the
eyeball in the absence of any other ocular (eye) disease or condition
and takes one of two forms:
Acute Glaucoma (also known as angle-closure
glaucoma) applies when the increase in eye pressure occurs suddenly
when the angle between the cornea and iris is reduced and the
aqueous
humour may drain from the eye. This is often painful
and accompanied by blurred vision.
Chronic Simple Glaucoma (also known as open-angle
glaucoma) is more common and applies when the increase in eye
pressure is gradual and usually painless. In this case the reduction
in quality of vision may also happen gradually and so be less
obvious to the patient.
This can sometimes happen in the cases of people who eyes do
not have higher than usual pressure, in which case it is referred
to as "low-tension glaucoma". |
Secondary Glaucoma |
Secondary Glaucoma refers to the situation in which another
disorder of the eye / visual system acts to impair the normal
(healthy) circulation of the aqueous
humour causing the pressure
inside the eye to increase. |
The main aim in treating glaucoma is usually to reduce the pressure
inside the eyeball(s) - which is called the intraocular pressure. Methods
commonly used to achieve this include the use of eye drops, and if
necessary surgery.
This section includes short definitions of clinical terms that refer
to disorders of the visual system. For definitions of other terms in this
category, choose from the list to the left.
Other related pages include the diagram
of the eye, definitions
of parts of the eye, and the section about clinical
procedures used to investigate the eye and visual system.
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