Glaucoma is a chronic disease and can potentially lead to blindness if it is not detected early
enough. When glaucoma happens or starts off, then it doesn’t have any symptoms in its
typical presentation so that is why it is important for everybody over the age of 40
to see the optician regularly because that’s one way where regular eye examination can
detect if the pressure within the eye is high enough, which is one of the ways that it can
be detected. So if the pressure is high within the eye and it is not treated, or low-ered,
then the high pressure can cause damage to the optic nerve which transmits the signals
from the eye to the brain and if the optic nerve is affected by the high pressure then
it stops working and that is how it leads to blindness.
This worsening of the health of the optic nerve from the high pressure is a one way
street, it is irreversible, so if somebody is detected when half of the optic nerve has
already been destroyed then we can treat and lower the pressure and control the condition,
but the field defects that have already happened because half of the optic nerve is not working
cannot be restored. However it is still important for treatment to go ahead because the rest
of the visual fields can then be saved.
The way in which glaucoma can be detected is by number 1: checking the intraocular pressure,
number 2: by examining the visual fields, the extent of damage or whether the fields
are intact and that is also done by the practice of the high street optometrists and also examination
of the back of the eye to look at the optic disc which is the front part of the optic
nerve and if there is any damage typical of glaucoma that that is another way to identify
if the disease is starting off.
Glaucoma also can have different atypical forms. This most common type of glaucoma does
not have any symptom, it is only by checking that we can identify if the disease is starting
off. There are other types which are less common and there is a type of glaucoma which
can present acutely and with symptoms like pain and headache and red eye where the pressure
goes high all of a sudden and that is called acute angle closure glaucoma. The most typical
one that I described is called open angle glaucoma. So when there is angle closure glaucoma
it is a medical emergency it is an emergency because if the pressure is not lowered within
an hour or so it can lead to permanent damage to the optic nerve and blindness. There is
a way we can identify by regular examination to see if the eye is at risk of potential
acute angle closure and that is by looking at the front part of the eye and doing an
examination called gonioscopy which looks at the an-gle of the anterior chamber.
If there is a narrow anterior chamber angle which is potentially at risk of angle closure
then a preventive laser treatment called laser iridotomy can create a small opening within
the iris which acts potentially like a safety valve so that if the angle does go into closure
and the pressure is rising, it can only rise so much and then the water will flow from
the posterior to the anterior chamber preventing a block and the pressure will never go that
high to lead to a full blown angle closure. So if we do identify patients who are at risk
of angle closure we recommend them to have what is called a laser iridotomy and that
is potentially a preven-tive measure to prevent angle closure.
There are other various types of glaucoma like congenital glaucoma which can be present
at birth, some-times very sadly they have already damaged the optic nerve and there
is blindness right from birth or from a very early age. There are other secondary types
of glaucoma which can lead from other conditions to pre-sent with a high intraocular pressure
like inflammation within the eye, steroid treatment for a long time, trauma to the eye
and various other conditions. If the pressure within the eye is not controlled in time,
then it can also lead to irreversible blindness.