There is risk of side vision loss due to eye pressure that causes damage to the optic
nerve. Blind spots occur in glaucoma and can develop into bigger areas that could
end up with tunnel vision. This is when central vision only remains - but even that
may be lost.
Fortunately there are glaucoma treatments available to try to prevent blind spots.
Symptoms of Glaucoma
There are different types of glaucoma. Most common is called open angle glaucoma,
and this seldom gives symptoms, as damage to optic nerve occurs gradually without
Therefore regular eye tests are important to detect glaucoma by the optician.
Closed angle glaucoma is less common and this causes a sharp rise in eye pressure
giving painful red eye that needs prompt treatment.
What is eye pressure ?
The eyeball can be thought of as a football. It needs some pressure in order to pump
the football into shape and is known as intraocular eye pressure. So eye pressure
is needed and amount varies.
However this pressure can be too much for the eye itself, and this physical force
may damage the optic nerve in the eye.
Eye pressure occurs from amount of fluid called aqueous humour. New fluid is produced
and then drained in a continuous cycle. If too much is produced or not enough drained,
then it may cause a rise in pressure.
What is normal eye pressure ?
The higher the pressure, the more the person is at risk of glaucoma but it does not
mean glaucoma will occur.
Some people can have higher eye pressure but not cause damage to the optic nerve
. However some people with low eye pressure can develop glucoma. There is ongoing
Even different thickness of cornea may have effect on pressure measurements. Also
eye pressure varies during the day.
Presently the NICE guidelines state eye pressure over 21 may be considered as a risk
factor and so the eye professional may decide to do other tests.
Other risk factors of glaucoma
Age; the risk of glaucoma increases with each decade of life. The optician may check
the eye pressure from about age 40.
Family history; risk increases if a family member has glaucoma.
If either Mother, Father, Son or Daughter has glaucoma already, then risk is four
If either Brother or Sister has glaucoma, then risk is about ten percent.
This could imply a genetic link.
The physical structure of the eyeball may pose a risk for glaucoma. For example
the drainage of fluid from the eye may be affected by shape and angle of drainage
Can glaucoma be treated ?
The disease cannot be reversed once damage has occurred but thankfully there is treatment
to prevent glaucoma getting worse.
Treatment of glaucoma is to try to reduce the eye pressure, usually by regular use
of eye drops. There are many different types of eye drops that reduce the pressure
of the eye. E.g. xalatan,azopt,betagan,combigan
Surgery may also be required depending on each individual case. Cataracts or other
eye conditions may be present that need to be managed.
Ongoing eye care is required to ensure the glaucoma is not getting worse so that
action can be taken.
Can I still drive with glaucoma ?
Glaucoma may cause large blind spot areas.
The eye specialist at the hospital will be able to give you further advice on driving
If there are large blind spots in both eyes - then there is greater risk of missing
people or cars to the side of you - and this is obviously dangerous in driving to
yourself and other people.
The DVLA may ask for a binocular field test - this is when both eyes are assessed
for blind spots - and if it is small, and there is good central vision, then it may
be ok to drive with glaucoma.
How does glaucoma cause field loss ?
The pressure in the eye exerts onto the optic disc, causing physical damage in glaucoma.
Normally signals from the retina ( central and side vision) pass to the optic nerve
and then it gets relayed back to the brain.
If the optic disc head is damaged due to pressure - then that information wont be
relayed back to the brain.
Therefore there will be blanks at side of vision - a person may not be aware of them
- esp if they are small
In glacoma, damage first occurs to the side vision - but if left untreated, then
central vision can be affected.