Glaucoma is a group of eye diseases 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.
Because you often cannot feel the pressure, and the damage happens slowly, you may not know you have glaucoma until a lot of damage has been done. That damage cannot be put right, so it is particularly important that you find out early.
The best way to make sure of this is to have a regular eye examination with an optometrist. If you are at risk of developing glaucoma, you should have an eye examination at least every two years, or more often if your optometrist recommends it.
If you have glaucoma but do not treat it, your eyesight will gradually get worse, and you could eventually go blind. The good news is that treatment with eye drops may stop it getting worse.
Who gets glaucoma?
Anyone can develop glaucoma. The risk of developing glaucoma goes up if you are:
• aged over 40
• very short-sighted
• of African or Caribbean origin
• closely related to someone with glaucoma.
If one of your parents or children, or a brother or sister, has glaucoma, and you are over 40, the NHS will pay for your eye examination.
How is glaucoma detected?
Because the early stages of 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 glaucoma. The first one is where your optometrist looks at the nerve at the back of your eye using a special torch called an ophthalmoscope, or a machine called a slit lamp. They may also take a photograph of the nerve. This can be useful for future visits, to help them see if things have changed.
The second test is where the optometrist measures the pressure inside your eye. This is done by gently pressing an instrument called a tonometer against it, this test does not hurt.
The third test is where the optometrist tests how wide your visual field is – how far you can see around you when you are looking straight ahead.
Sometimes you can have glaucoma even if you have low 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 glaucoma, so your optometrist or ophthalmologist (a specialist eye doctor) will tell you how often you should have this check
What will happen if I have glaucoma?
If your optometrist suspects that you may have glaucoma, he or she will refer you to an ophthalmologist. If you do have 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 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.
I have glaucoma. Can I drive?
If you drive a car and have been diagnosed with glaucoma in both eyes, this will affect the amount you can see, and the law says that you must tell the DVLA (Driver and Vehicle Licensing Authority). You may have to take some extra tests, but most people are still allowed to carry on driving.
You can find out more at www.direct.gov.uk/driverhealth
This is a type of glaucoma where the drainage channels of your eye are blocked or damaged in some way. Sometimes the increased pressure can come and go, and some people get short bursts of pain and blurred vision. This can happen when your pupil gets bigger, so it may be at night or when you are in a dark area (like the cinema). Other symptoms are an ache in the eye which comes and goes, red eyes, or seeing haloes around lights. Or it can be a bit like looking through a haze or mist.
People who are more likely to get closed-angle glaucoma are people over 40, women, people of Asian origin, people with a family history of closed-angle glaucoma, and people who are very long-sighted.
For more information:
• visit www.glaucoma-association.com
• Visit NHS Choices
• phone SightLine on: 01233 648170 (an information, support and advice service provided by the International Glaucoma Association)