Glaucoma is the name of an eye condition in which the optic nerve, which connects your eye to your brain, is damaged by the pressure of the fluid inside your eye. This may be because the pressure is higher than normal, or because the nerve is more susceptible to damage from pressure. This may affect one or both of your eyes. There are two main types of glaucoma: chronic glaucoma, which is the most common, happens slowly and doesn’t cause any pain. If left untreated, over a period of time, the field of vision gradually becomes impaired. Acute glaucoma is much less common. This happens when there is a sudden rise in eye pressure which can be very painful. The affected eye becomesred and sight deteriorates. Vision may seem misty with coloured rings around white lights. There may even be nausea and vomiting. It will cause permanent damage to your sight if not treated properly.
Who is at risk of chronic glaucoma?
Anyone can develop chronic glaucoma. The risk of developing chronic glaucoma increases if you:
are aged over 40
are very short-sighted
are of African or Caribbean origin
are closely related to someone with chronic glaucoma
have raised pressure within your eye. This is called ocular hypertension (OHT).
If one of your parents or children, or a brother or sister, has glaucoma, then you should have regular eye tests. This is especially important if you are age over 40.
How is chronic glaucoma detected?
Because the early stages of chronic glaucoma do not cause symptoms, the best way to catch it early is to have regular eye examinations.
There are three main tests to see if you have chronic glaucoma. The first one is where your optometrist/eye doctor looks at the optic nerve at the back of your eye using an ophthalmoscope, or a slit lamp to shine a light into your eye. They may also take a photograph or a scan of the nerve. This can be useful for future visits, to help them see if things have changed. The second test is where the pressure inside your eye is measured. This may be done by using a machine which gently blows a puff of air at your eye or by numbing your eye with drops and then gently pressing an instrument called a tonometer against it. The tests do not hurt, although the puff of air may make you jump a bit. The third test is the visual field test/peripheral vision test – how far you can see around you when you are looking straight ahead. Sometimes you can have chronic glaucoma even if you have normal eye pressure, which is why you will usually have at least two of these three tests. If the results are not clear, you may be asked to do one or more of the tests again on a different day.
I have been told that the pressure inside my eye is high, but I do not have glaucoma
Some people naturally have pressure that is above the normal range, but this pressure does not cause any damage to their eyes. This means they do not have glaucoma. However, they are more likely to develop chronic glaucoma, so your optometrist or ophthalmologist (a specialist eye doctor) will tell you how often you should have this checked.
What will happen if I have chronic glaucoma?
If your optometrist suspects that you may have glaucoma, he or she will refer you to an ophthalmologist. If you have chronic glaucoma, you will be given eye drops to use every day. They will reduce the pressure and help control the build-up of fluid. They will not hurt. Because you will not feel different in any way, you will not be able to tell that the treatment is working. This is why it is very important that you:
go to your follow-up appointments; and
keep on using the drops. If you find it hard to use the eye drops, you can get special bottles or holders to make it easier.
In a small number of cases, an ophthalmologist may recommend that you have an operation to help drain away the fluid. There is no cure for chronic glaucoma but it can be treated effectively, normally with eye drops. Any existing eye damage will probably be permanent, but your sight could get much worse if you stop the treatment. It is very important that you use the eye drops every day, even if you cannot tell that they are helping.
Although damage already done cannot be repaired, with early diagnosis and treatment, damage can usually be kept to a minimum.
Acute glaucoma. Who is at risk?
This is a type of glaucoma where the drainage channels inside your eye are blocked or damaged in some way. This causes the pressure inside your eye to increase rapidly.
Sometimes the increased pressure can come and go, and some people get short bursts of pain and/or discomfort and blurred vision. People who are more likely to get acute glaucoma are:
people over the age of 40
women
people of East Asian or South Asian origin
people with a family history of closed-angle glaucoma
