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A group of conditions
which can seriously affect the vision by compromising the function
of the optic nerve (the nerve that relays the visual messages from
the eye to the brain enabling us to see), commonly accompanied by
a rise in the pressure within the eye ball. Within an elaborate
classification there are two important types chronic glaucoma and
acute glaucoma. Chronic glaucoma is more common of the two and is
often just called glaucoma. The affection of sight is mainly in
form of gradual narrowing of field of vision which may ultimately
result in tunnel vision or even blindness.
Generally people over 40,
but people of any age including new born babies can get it. It has
a tendency to run in the family. People of African origin are at a
higher risk of getting it. Short sightedness and diabetes are also
risk factors.
Genetic factors play an
important role. There is an abnormality in the drainage of
fluid (aqueous) from the eye, thereby raising the pressure within
the eye ball (in most cases). The end result is a gradual loss of
function of the optic nerve. The nerve as seen during the eye
examination appears paler and what is known as "cupped".
In case of acute glaucoma the drainage of fluid is blocked more
rapidly causing a fast rise in the pressure which can give rise to
pain.
Usually none in the early
stages of chronic glaucoma. Later when the field of vision gets
affected significantly one may experience loosing a part of
the vision, commonly the sides. Very advanced stage can even cause
blindness. There is usually no pain involved. In acute glaucoma
,however there can be severe pain in the affected eye. There is
also blurred vision and redness of the eye. In early stage haloes
may be seen around lights.
- CAN
I DO SOMETHING ABOUT IT?
Early diagnosis is very
important , so if there is a close relative in the family with
glaucoma then one must get an eye test regularly. The optician can
do a preliminary pressure check and refer you to an
ophthalmologist (eye doctor) for further tests if required. In UK
you can get a free eye test if you have a family history of
glaucoma. People who are already receiving treatment for glaucoma
should make sure they use it regularly, attend the eye clinic
regularly and follow the doctors advice.
No, but it can certainly
be controlled. With early detection and regular treatment the
damage to the sight can be limited or further worsening can be
stopped.
Initially usually,
treatment in form of eye drops is given with regular monitoring of
the disease. Regular use of the drops as per the advice of the
doctor is crucial. For monitoring, the pressure is checked, the
condition of the optic nerve is examined and the visual field is
assessed. Surgical treatment is usually resorted to in resistant
or severe cases and may obviate the use of medications. Glaucoma
medications can have some adverse effects and these can be
discussed with the eye doctor. In case of adverse effects
alternative medication can be tried or surgery resorted to.
Trabeculectomy is the
standard surgery undertaken for glaucoma. It involves formation of
a passage for the fluid within the eye (aqueous) to drain outside
the eye in a somewhat controlled fashion. The fluid collects under
the skin of the eye (conjunctiva) forming a sort of a small
blister on the upper part where it hides under the lid. The
procedure is slightly unpredictable in that the amount of fluid
draining out can be too much or too little, or indeed nil. If it
is too much the eye pressure can reduce too much. After the
initial crucial period following surgery, the pressure in most
cases does settle down to a more desirable level. Risks and
complications include failure to lower the pressure, infection,
haemorrhage and cataract etc. Viscocanalostomy is a
newer surgical procedure and is still not very popular. |
Raised pressure within
the eye affects the optic nerve.
Representation of the
field of vision, the black areas indicating loss of vision
optic nerve
head showing cupping-the paler area in the center.
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