Glaucoma - Understanding the Basics
Copyright 2006 Anne Wolski
One of the most common causes of blindness for people aged over
forty years is glaucoma and it affects around one in fifty
people in this age group. People are often unaware that they
even have this condition as they may not suffer from any obvious
symptoms. Nonetheless, it is important that it is detected early
to avoid severe deterioration of sight.
The eye is separated into anterior and posterior chambers by the
lens and by a muscle, called the ciliary muscle, which supports
it. There is also a structure called the ciliary body which
manufactures a fluid called aqueous humor that fills the
anterior chamber. This needs to be continuously drained and,
when glaucoma is present, this does not happen. This causes
pressure in the eyeball to rise, thus causing problems with
sight.
There are three major types of glaucoma and they are as follows:
1. Angle closure glaucoma 2. Open angle glaucoma, and 3. Narrow
angle glaucoma
The angle is where the iris meets the cornea. It is also where
the fluid drains from the eye.
In angle closure glaucoma, the angle gets blocked. Fluid
continues to be made but is unable to drain. Because of this,
the pressure in the eye builds up to a level which is harmful.
With open angle glaucoma, the angle stays open but fluid builds
up when the structure at the back of the angle becomes blocked.
Narrow angle glaucoma is a condition where the iris and the lens
touch, trapping fluid. The iris bulges forward, effectively
closing off the drainage angle and causing acute glaucoma.
Other types of glaucoma include:
1. Congenital glaucoma 2. Pigmentary glaucoma, and 3. Secondary
glaucoma
Congenital glaucoma is rare and affects infants. These children
are normally diagnosed by the age of one and are usually born
with a defect in the drainage system of the eye.
Pigmentary glaucoma is also rare and happens when the pigment
from the iris blocks the drainage system. The system is
eventually damaged because of the inflammation caused by this
condition.
Secondary glaucoma is normally caused by injury, infection,
tumor, inflammation or and enlarged cataract. Any of these
conditions can lead to secondary glaucoma.
Often, people with glaucoma don't even realize that they have a
problem as there are no obvious symptoms. The eyesight
deteriorates so gradually that it is often unnoticed. The only
real way of knowing that glaucoma is present is by a physical
examination of the eye by a doctor or optometrist who may be
able to see the problem by examining the eye with an
ophthalmoscope.
An optometrist may notice if there are any areas of blindness in
the part of the eye that is not used for detailed vision. This
is the area affected with glaucoma initially. The area of the
eye used for detailed vision is not affected at first and this
is why people don't notice the onset of glaucoma for some time.
Treatment usually consists of drops that are placed in the eye
three or four times daily to improve the rate of fluid drainage.
Sometimes, surgery may be required to create a new outlet for
the fluid. Treatment does not always work and, in some cases,
the person may become progressively blind no matter what
treatment is used. Once sight has been lost, it cannot be
restored, so early diagnosis and treatment are essential.