Ask the expert: what is glaucoma?

Glaucoma is an eye condition that leads to damage to your optic nerve, the nerve that connects your eyes to your brain. It’s often caused by abnormally high pressure inside the fluid of the eye. Over time, this increased pressure can damage the optic nerve, causing vision loss and eventually blindness, if left untreated. 

What causes increased pressure inside your eye?

The fluid in your eyes usually flows out through a drainage channel at the same rate as it is made, in a continuous cycle. If this channel gets blocked, fluid can build up, increasing the pressure inside your eye. 

Factors that increase your risk of raised pressure inside your eyes include:

• Certain medications
• Dilating eye drops
• High blood pressure
• Poor blood flow to the optic nerve

What are the different types of glaucoma? 

The most common type of glaucoma is open-angle glaucoma, where the drainage channel of your eye becomes gradually clogged, causing your eye pressure to slowly increase over time. You may not notice any symptoms until the advanced stages, so it’s important to have regular eye tests so your optometrist can pick up the early signs.

Closed-angle glaucoma happens when the space between your iris (the coloured part of your eye) and the cornea (the protective outer layer of your eye) suddenly narrows or closes and blocks the drainage channel. This causes pressure to rapidly build up and is a medical emergency. It is very painful and causes symptoms such as:

• Blurred vision
• Headaches
• Nausea and vomiting
• Red eyes
• Seeing halos around lights

If you experience any of these symptoms call 999 or visit A&E immediately. Closed-angle glaucoma can seriously damage your vision very quickly.

When does glaucoma start?

Open-angle glaucoma can occur at any age but is more common later in life, after age 60.

How is glaucoma detected? 

Open-angle glaucoma is often symptomless in the early stages. By the time you notice symptoms, glaucoma has likely already caused permanent damage to your vision. Early detection is therefore key to preserving your vision. Glaucoma can be picked up by your optometrist at a regular eye test.

They will perform a series of tests, including a tonometry test where a puff of air is blown into your eyes by a machine to measure your eye pressure. 

As glaucoma damages the optic nerve, it can affect your field of vision and cause blind spots. This can be detected during a visual field test, where you will be shown a sequence of light spots and asked to press a button to indicate which you can see. 

Your optometrist will also examine the back of your eye to check for damage, using either a microscope and a light or an optical coherence tomography (OCT) scanner. 

If they suspect you have glaucoma, they may perform a gonioscopy to try to determine the cause of your glaucoma. This is an examination of the front of the eye to see whether the space between your iris and cornea is open or closed and if there is any other damage to your eye.

Are there effective treatments? 

Glaucoma cannot be cured but treatments can slow progression and prevent any further vision loss. The most common first-line treatment is daily eye drops that lower the pressure in your eyes or help decrease fluid production. You’ll need to use these for the rest of your life to manage the condition. If eye drops are not effective, surgery may be needed, after which you will need to continue to use eye drops.

Is laser treatment effective? 

Laser surgery can help to reduce the pressure in your eyes if you have open-angle glaucoma.

Is surgery an option for glaucoma treatment? 

There are different types of glaucoma surgery. The most common type is a trabeculectomy. It reduces pressure in the eye by draining some of the fluid through the white part of your eye (called the sclera).

Are cataracts and glaucoma connected?

Cataracts are cloudy patches within the lenses of your eyes, which can cause blurry vision and sight loss. Both cataracts and glaucoma are more common with age, but they’re not usually connected. In rare cases, cataracts can cause your lens to become thicker and make it more difficult for fluid to drain away — this can increase the pressure in your eyes, putting you at greater risk of glaucoma. Cataracts can be treated with surgery, which will reduce any build-up of pressure within your eyes.

Can I manage glaucoma with lifestyle changes? 

Yes, there are simple lifestyle changes you can make to help manage your condition. These include eating a healthy, balanced diet and exercising regularly, quitting smoking and avoiding stressful situations.