Glaucoma is usually picked up during a routine eye test, often before it causes any noticeable symptoms.
It's important to have regular eye tests soproblems such as glaucoma can be diagnosed and treated as early as possible. Early treatment can help stop your vision becoming severely affected.
You should have an eye test at least every two years. If you're at a higher risk of glaucoma, for example if you have a close relative with it, you may be advised to have more frequent tests.
You can getan eye test at a local opticians. Find an opticians near you.
Some people can receive free eye tests on the NHS. Find out if you're entitled to free NHS eye tests.
There are several quick and painless tests that can be carried out to diagnose and monitor glaucoma.
An eye pressure test (tonometry) uses an instrument called a tonometer to measure the pressure inside your eye.
A small amount of anaesthetic (painkilling medication) and dye is placed onto the front ofyour eye. A light from the tonometer is gently held against your eye to measure the pressure inside.
High pressure inyour eye can be a sign that you have glaucoma or are at increased risk of developing it.
Gonioscopy is an examination of the front outer edge of your eye, between the cornea (transparent layer at the front of your eye) and the iris (the coloured part of your eye).
This is the area where the fluid should drain out of your eye.
A gonioscopy can help to determine whether this area (called the "angle") is open or closed (blocked), which can affect how fluid drains out of your eye.
A visual field test sometimes called perimetry checks for missing areas of vision.
You maybe shown a sequence of light spots and asked which ones you can see. Some dots will appear in your peripheral vision (around the sides of your vision), which is often affected by glaucoma to begin with.
If you can't see the spots in your peripheral vision, it may indicate the glaucoma has damaged your vision.
The optic nerve (the nerve connecting your eye to your brain) can become damaged in glaucoma, so an assessmentmay be carried out to see ifit's healthy.
For the test, eye drops will be used to enlarge your pupils. Your eyes are then examined with aslit lamp (a microscope with a bright light) to assess your optic nerve.
The eye drops used to widen your pupils could temporarily affect your ability to drive, so you'll need to make arrangements for getting home after your appointment.
Optical coherence tomography (OCT) is a type of scan where special rays of light are used to scan the back of your eye and produce an image of it.
This can help detect any damage to the retina (the light sensitive layer at the back of the eye) or optic nerve caused by glaucoma.
If glaucoma is picked up during an eye test, you should be referred to anophthalmologist (eye doctor) for further tests.
Your ophthalmologist will confirm your diagnosis and find out:
He or she will then be able to advise on treatment. See treating glaucomafor more information.
In some cases, your ophthalmologist will continue to treat you. But for less serious types of glaucoma, you may be referred back to the opticians for your treatment.
Find out about glaucoma, including what it is, what the symptoms are, why it happens and how it's treated.
Find out about the main types of glaucoma, including open angle glaucoma and angle closure glaucoma.
Find out why glaucoma happens, including what can increase your risk of developing the condition.
Find out where to get tested for glaucoma and what tests may be carried out to diagnose the condition.
Find out about the main treatments for glaucoma, including eye drops, laser treatment and surgery.
Read about Linda Moore, who has had open angular glaucoma since she was 39.She runs the Poole Glaucoma Support Group, which supports people with glaucoma.