Glaucoma
is a leading cause of blindness. In most cases there are no warning
signs. Having regular eye checks will help detect the onset of the
disease. Blindness is preventable if glaucoma is diagnosed and treated
early enough in the course of the disease.
What is Glaucoma
?
It
is an eye condition characterised by loss of vision due to damage
of
the optic nerve. The optic nerve carries sight images to the brain,
any damage to the nerve results in damage to sight. Usually, but
not always, glaucoma is accompanied by an increase in intra-ocular
pressure (IOP) (pressure within the eye). It is the pressure that
damages the nerve.
The
different types of Glaucoma ?
-
Chronic (primary open angle) glaucoma
- this form usually affects both eyes and develops slowly so that
loss of sight is gradual. There is no pain, redness of the eye
or dramatic change in vision.
-
Acute (angle closure) glaucoma
- there is a sudden increase in the intraocular pressure of one
eye. The eye becomes red and painful. Often there is mistiness
of vision and episodes of seeing haloes around lights.
-
Secondary glaucoma
- in this group of conditions an increase in the intraocular pressure
is caused by other diseases of the eye.
- Congenital
glaucoma
(buphthalmos)
- is a condition where glaucoma is present from birth. An increase
in intraocular pressure causes the eye to enlarge.
NB:
The rest of these pages will concentrate
only on chronic open angle glaucoma.
What
causes the pressure to rise?
The contents
of the eyeball are nourished by a fluid (aqueous humour). This fluid
is NOT the same as tears. Aqueous is secreted by a tissue within the
eye called the ciliary body It circulates around the structures within
the eyeball and leaves the eye via the trabecular meshwork sited in
the anterior chamber at the front of the eye. An increase in intraocular
pressure in chronic open angle glaucoma occurs when there is progressive
obstruction within the trabecular meshwork. It is this persistent
increase in intraocular pressure which may damage the optic nerve
and cause sight to be lost. This eye pressure is not the same as blood
pressure. |
