WHAT IS GLAUCOMA?
Glaucoma is a group of eye conditions that affect vision. When the eye is functioning normally, fluid is produced inside the eye and is drained away through the drainage channel. The balance between the production and drainage of the fluid creates a normal amount of pressure in the eye, which is needed for the eye to maintain its shape and function. If the fluid cannot drain away properly, the pressure in the eye rises. If the pressure is too high, the optic nerve at the back of the eye becomes damaged. Your optic nerve is important for sight because it’s the pathway for the signals from your retina, the light sensitive cells at the back of your eye, to your brain. This pathway allows you to “see” the world around you.
The diagnosis of glaucoma is given when there is evidence of optic nerve damage.
How will it affect my sight?
Typically the peripheral vision is lost first and so goes unnoticed because the central vision, for reading and recognising faces, remains good. Also, one eye can make up for vision loss in the other eye, until both eyes have lost vision in the same area.
If left untreated, the damage continues (‘progresses’), usually slowly over years and may eventually affect your ability to drive or make you more likely to fall.
In glaucoma vision loss is permanent and cannot be recovered. However with early diagnosis, careful monitoring and regular use of the treatments, the vast majority of people with glaucoma retain useful sight for life.
Will I have any symptoms?
You can’t “feel” primary open angle glaucoma; it doesn’t cause any symptoms and the eye pressure doesn’t cause any pain. You may not notice any difference in your vision because glaucoma affects your peripheral vision (also known as your side vision) first. As your peripheral vision is not as sensitive as your central vision, it’s difficult to notice any early changes to your vision – but your sight is being damaged.
Because you may not notice a problem until your glaucoma is more advanced, it’s important to have regular eye tests as this is the only way to know if you have it. The earlier your glaucoma is picked up and treated, the more of your sight can be protected.
Are Some People More Susceptible to Glaucoma?
Anyone can develop glaucoma but some factors can put you at more risk. These include:
Your age: Glaucoma is more common as you get older. It occurs in two per cent of people over the age of 40, increasing to almost 10 per cent of people over the age of 75.
Blood pressure: People with low blood pressure have a greater risk of worsening of glaucomatous sight loss. The eye doctor may want to review blood pressure treatment, if it is being taken, to ensure that it is not contributing to the low blood pressure.
Your race: If you’re from an African-Caribbean ethnic background, then you may be at a higher risk of developing open angle glaucoma. It’s also more likely to develop earlier in life – before the age of 40, and there is a chance that it may develop more quickly.
Being of East Asian origin can increase your risk for closed angle glaucoma.
Your family history: You’re at a higher risk of developing glaucoma if you have a close blood relative (a parent, brother, sister or child) with glaucoma. If you’ve been diagnosed with glaucoma, let these close family members know. If they’re over 40, they should see their optician every year, and they won’t have to pay for their eye examinations.
Your eyesight prescription: Being short-sighted can increase your risk of developing open angle glaucoma. Closed angle glaucoma is more common in people who are long-sighted.
Diabetes: People with diabetes may be at increased risk of developing glaucoma, although it is not known whether there is a direct link between the two conditions. However, all people with diabetes should have regular routine eye examinations for diabetic eye diseases and glaucoma tests can usually be requested at the same time.
Steroids: If you have used steroids for a long period of time, you may develop glaucoma.
What types of Glaucoma are there?
Primary open angle glaucoma where damage to the optic nerve occurs slowly over a long period of time due to your eye pressure increasing to more than 21mmHg.
Closed angle glaucoma where damage to the optic nerve can happen very quickly due to a sudden rise in eye pressure.
Normal tension glaucoma occurs when damage to the optic nerve even when the eye pressure is within the normal range that means less than 21mmHg. It’s not entirely known why some people’s optic nerve becomes damaged even though their eye pressure is at a normal level. It’s thought that perhaps some people’s optic nerve may just be weaker and unable to cope with an eye pressure within the normal range.Normal tension glaucoma is treated in the same way as open angle glaucoma – by lowering your eye pressure to a level which is right for you, to keep your sight safe.
Secondary glaucoma which occurs as a result of another eye condition, an injury to the eye or due to medication.
Congenital glaucoma, when a baby is born with glaucoma.
What is Ocular hypertension (high eye pressure)
Some people naturally have eye pressure above the normal range, but this pressure doesn’t cause any damage to their optic nerve. This is described as ocular hypertension rather than glaucoma.
Different people can have different optic nerve strengths, and some people’s optic nerves stay healthy at higher than normal eye pressures.
Most people’s eye pressures are in the range of 10 to 21mmHg. If you have an eye test and your eye pressure is higher than 21mmHg, your optometrist may refer you to the hospital for more tests. These tests will check whether this higher eye pressure is likely to cause any problems to your optic nerve.
A high pressure may be completely normal for your eye.
Treatment for Glaucoma
Treating Primary Open Angle Glaucoma
The aim of treating POAG is to reduce the pressure within the eye to a level at which no further damage occurs to the optic nerve. Initial treatment is usually with eye drops.
Eye drops and glaucoma
These may reduce the amount of fluid being produced by the eye, increase the rate of drainage of fluid from the eye, or both.
These are sufficient to keep the pressure in the target range in most people. There are several different types of eye drop for glaucoma and we may need to change your treatment until the right drop, or combination of drops, is found. Once eye drops have been started, they usually need to be taken for life (there is no such thing as a ‘course of treatment’ for glaucoma). It is worth getting into a routine so that the drops are not forgotten. See our video on “ "in the patient information section.
Laser treatment may also be effective and is sometimes offered instead of, or in addition to, eye drops. If the eye drops do not provide a sufficient pressure lowering effect, surgical treatments are available.
Treating Ocular Hypertension
Ocular hypertension can increase your risk of developing glaucoma so this needs to be monitored. Sometimes you may be prescribed eye drops to help reduce your eye pressure and reduce your risk of developing glaucoma.
Laser treatment is applied to the trabecular meshwork, which helps it to work and drain fluid better, lowering your eye pressure.
In a very small number of people with glaucoma (approx 5%), eye drops or laser treatments aren’t successful in keeping the eye pressure stable. In these cases, surgery may be an option and the most common operation is a trabeculectomy.
Managing your glaucoma
Having glaucoma may mean you need to make a few changes to your everyday life in order to prevent sight loss. For most people, this includes taking eye drops daily and having to attend regular hospital visits to make sure your eye pressure stays stable. This is because changes in eye pressure have no symptoms, and without regular checks you won’t be able to tell that your treatment is working. It also gives you a good opportunity to ask any questions you may have about your glaucoma treatment.
You’ll have a regular visual field test done at your eye clinic visits, which helps us monitor how your glaucoma is affecting your sight and it allows us to make the right decisions about your treatment.
What if my glaucoma cannot be fully controlled?
More than 90 per cent of people diagnosed with glaucoma today will retain useful vision (blindness is rare).
In certain cases, however, it may not be possible to control the glaucoma well enough to retain useful vision. This is often where the condition has been diagnosed at a late stage, treatments have been ineffective, or where the person with glaucoma has had difficulty taking the prescribed medications.
It’s completely natural to be upset when you’ve been diagnosed with glaucoma and it’s normal to find yourself worrying about the future and how you will manage with a change in your vision.
It can sometimes be helpful to talk about these feelings with someone outside of your circle of friends or family. We can help you find someone to provide you with further practical and emotional support about your eye condition.
Can I continue to drive with glaucoma?
Most people are still able to drive, provided that their visual field loss is not severe. However, if you have glaucoma in both eyes, you must, by law, inform the Driver and Vehicle Licensing Authority (DVLA) about your condition and undergo a special visual field test in order to check the extent of damage to your sight. More information can be Driving and Glaucoma