Sunday, 19 March 2017


Credit:VickieRobert Hospitality (VRH)



Eye pressure is largely independent of blood pressure.

Glaucoma is a disease that damages the optic nerve, the part of our eye that carries the images we see to our brain. In the healthy eye, a clear liquid circulates in the front portion of the eye. To maintain a constant healthy eye pressure, the eye continually produces a small amount of this fluid and an equal amount which flows out of the eye. If you have glaucoma, the fluid does not flow properly through the drainage system. Fluid pressure in the eye increases and this extra force presses on the optic nerve in the back of the eye, causing damage to the nerve fibres. Glaucoma is an extremely serious eye disorder which can cause blindness if not treated early.

What controls pressure in the eye?


Why is increased eye pressure serious?



In the early stages of chronic glaucoma, there are frequently no obvious symptoms and whilst increased pressure in the eye may be an indicator, this will not necessarily mean you have the disease. With fewer early warning signs than other major eye diseases, the most efficient detection method for glaucoma is by regular eye examination. Those most prone to developing glaucoma are people over 60 and people with a family history of the disease.

Types of Glaucoma

There are four main types.

Chronic glaucoma: The most common is chronic glaucoma in which the aqueous fluid can get to the drainage channels (open angle) but they slowly become blocked over many years. The eye pressure rises very slowly and there is no pain to show there is a problem, but the field of vision gradually becomes impaired. In Ireland when people talk about &lsquo;glaucoma&rsquo; they are mostly referring to this chronic type, sometimes referred to as &lsquo;primary open angle glaucoma&rsquo;.

Acute glaucoma: Acute glaucoma is much less common in western countries. This happens when there is a sudden and more complete blockage to the flow of aqueous fluid to the eye. This is because a narrow &ldquo;angle&rdquo; closes to prevent fluid ever getting to the drainage channels. This can be quite painful and will cause permanent damage to your sight if not treated promptly.

Secondary and developmental glaucoma: There are two other main types of glaucoma. When a rise in eye pressure is caused by another eye condition this is called secondary glaucoma. There is also a rare but potentially serious condition in babies called developmental or congenital glaucoma which is caused by malformation in the eye.

Is glaucoma common?

Figures for the UK and Ireland suggest some form of glaucoma affects about two in 100 people over the age of 40.


Are some people more at risk of chronic glaucoma?

Yes. There are several factors which increase the risk.
Family: f you have a close relative who has chronic glaucoma then you should have an eye test at regular intervals. You should advise other members of your family to do the same. This is especially important if you are aged over 40 when tests should be done every year.
Short sight: People with a high degree of short sight are more prone to chronic glaucoma.
Diabetes is believed to increase the risk of developing this condition.

Is there a risk of sight loss?


The early loss in the field of vision is usually in the shape of an arc a little above and / or below the centre when looking ‘straight ahead’. This blank area, if the glaucoma is untreated, spreads both outwards and inwards. The centre of the field is last affected so that eventually it becomes like looking through a long tube, so-called ‘tunnel vision’. In time even this sight would be lost.


As glaucoma becomes much more common over the age of 40 you should have eye tests at least every two years.


While there is no cure for glaucoma and optic nerve damage cannot be reversed, the disease can be treated successfully and vision loss prevented by early detection. Treatment involves controlling the pressure in the eye as it is pressure which damages the optic nerve causing loss of sight. Acute glaucoma is treated by drugs to relieve pressure and may be followed by laser treatment or surgery to allow the fluid to drain. Occasionally, the blockage in the eye becomes permanent and needs the same treatment as chronic glaucoma. Chronic glaucoma is controlled by eye drops, or occasionally by tablets. Where vision continues to deteriorate, laser treatment or surgery to provide a drainage valve will be required. These procedures have a high success rate. They can control the pressure and stop the progression of the disease, although it is important to remember it cannot be cured and lifelong monitoring is essential.

Treatment to lower the pressure is usually started with eye drops. These act by reducing the amount of fluid produced in the eye or by opening up the drainage channels so that excess liquid can drain away. If this does not help, your eye doctor may suggest either laser treatment or an operation called a trabeculectomy to improve the outflow of fluids within the drainage system of your eye.

Is there a cure?



In acute glaucoma the pressure in the eye rises rapidly. This is because the periphery of the iris and the front of the eye (cornea) come into contact so that aqueous fluid is not able to reach the tiny drainage channels in the angle between them. This is sometimes called closed angle glaucoma.



Sometimes people have a series of mild attacks, often in the evening. Vision may seem ‘misty’ with coloured rings seen around white lights and there may be some discomfort in the eye. If you think that you are having mild attacks you should contact your doctor without delay. In routine examinations the structure of the eye may make the examiner suspect a risk of acute glaucoma and advise further tests.






Can it be cured?


Will it affect my Driving?

Most people can still drive if the loss of visual field is not advanced. To assess possible damage to your peripheral vision you will need a special test to see whether your sight meets the standards of the Driver and Vehicle Licensing Authority. Often people who have damaged field of vision on the detailed tests which are done to monitor progession of the disease, can still have a good enough field of vision for everyday activities such as driving so always ask your eye doctor if you should do an Estermann test before deciding if you are fit to drive .

Will I have sight loss?



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