Glaucoma is an eye disease that damages the optic nerve — the nerve that connects your eyes to your brain — and ultimately can cause vision loss. Although glaucoma can’t be cured, its progression can be slowed. If left untreated, glaucoma can lead to blindness — in fact, it is one of the main causes of blindness for people over 60 in the UK. Having regular eye tests is essential to keep your eyes healthy and pick up any early signs of glaucoma.
Glaucoma is caused by an increase in your intraocular pressure — this is the pressure in your eye due to the fluid contained within it. Raised intraocular pressure can damage your optic nerve.
Fluid in your eyes is constantly renewed ie it is produced and drains out in a continuous cycle. Your intraocular pressure can become raised if your eye retains too much fluid. This can happen when the channels that usually drain fluid out of your eyes become blocked.
There are several different reasons why your channels can become blocked; depending on the cause, you may be diagnosed with a particular type of glaucoma.
Glaucoma usually affects both eyes, but can be worse in one eye. If your glaucoma is caused by injury (traumatic glaucoma), then it will only affect the injured eye. Traumatic glaucoma is less common than other types of glaucoma and is usually caused by blunt trauma, which may cause bleeding and the formation of debris — this can block the drainage channel of the eye.
Glaucoma can run in families but usually only develops in later life.
You are more at risk of developing glaucoma if you:
Chronic (long-term) glaucoma
Also known as open-angle glaucoma, this is the most common type of glaucoma, seen in 90% of cases. It happens when the drainage channels of your eyes gradually become clogged, causing fluid to slowly build up over time and your intraocular pressure to gradually rise.
Acute angle-closure glaucoma
This condition is caused by a sudden increase in pressure in your eye and requires urgent medical attention to prevent permanent damage to your sight. It’s very painful and happens when the iris (the coloured part of your eye surrounding your pupil) and cornea (the transparent layer at the front of the eye) move closer together suddenly and block the channels that allow fluid to drain from the eye.
This refers to glaucoma that is caused by an underlying eye condition, an eye injury (traumatic glaucoma) or medication.
This is a more unusual type of glaucoma where the optic nerve has been damaged even though the pressure in the eye is not considered too high.
This rare type of glaucoma occurs in babies where the drainage channels in the eyes failed to develop properly in the womb. This type of glaucoma can be hereditary.
For many people, glaucoma develops gradually and with open-angle glaucoma, there may be no symptoms until the disease is well-established.
In acute angle-closure glaucoma, blindness can happen overnight, which is why it’s treated as a medical emergency.
It’s important to have your eyes tested every two years, where your optometrist can check for glaucoma. If you experience any of the following symptoms, you should book an eye test straight away:
Your optometrist will carry out several tests to check for early signs of glaucoma.
The first test is the tonometry test, which checks your eye pressure — high pressure can lead to the rapid development of glaucoma. Your peripheral vision will also be checked using a visual field test. Your optometrist will then use eye drops to dilate your eyes so that the optic nerve can be examined.
Imaging techniques will also be used to check the condition of your optic nerve.
Lowering the pressure in your eyes will slow down the progression of glaucoma. Your optometrist will discuss any medications you’re taking as some can make the condition worse and you may need to switch to alternatives. They’ll also suggest lifestyle changes to keep your eyes healthy.
Regular eye tests will help monitor the progression of your glaucoma and your optometrist may refer you to an ophthalmologist, a doctor specialising in eye health.
Glaucoma is usually treated with medication, laser treatment or surgery. None of these can reverse the damage to your vision but they can help prevent further vision loss.
Special eye drops that regulate fluid levels in your eyes can help reduce your intraocular pressure. It’s important to use the eye drops exactly as prescribed and to report any side effects to your doctor.
Laser therapy is usually used to treat open-angle glaucoma if eye drops are not reducing your intraocular pressure enough. It is performed under local anaesthetic and involves using a small laser beam to open up the drainage channels in your eyes to allow fluid to drain out.
It may take several treatments to be effective — you may therefore need to have the procedure repeated every few years. You may still need to use eye drops after having laser treatment.
Different surgical procedures can be used to lower the eye pressure or to draw excess fluid away from the eyes, usually if eye drops are not effective enough.
Trabeculoplasty is when a flap is created in your eye to allow fluid to drain away. Alternatively, small tubes called Baerveldt tube shunts are inserted to improve fluid drainage. Both of these procedures are carried out under general anaesthetic and you’ll need around six weeks to recover.
Minimally invasive glaucoma surgery (MIGS) uses microscopic equipment to insert either a tiny titanium tube or a stent made from natural gelatin into the eye to help the fluid to drain. MIGS has a shorter recovery time than a trabeculoplasty and can be performed under local anaesthetic.
Glaucoma can be effectively treated with several different approaches. Left untreated, however, it puts your vision at risk. It’s therefore important to get your eyes tested regularly to make sure any early signs of glaucoma are picked up before your vision deteriorates and so you can begin treatment as soon as possible.