Glaucoma – causes, symptoms and treatment
What is glaucoma?
Glaucoma is a group of eye conditions that occur when there is a build-up of pressure inside the eye. The fluid in the eye (called the aqueous humour) helps to provide your eye with nutrients and support its shape; your eye continually produces and drains away this fluid. When the fluid starts to drain away slower than it is produced, the pressure in the eye increases, which can result in damage to the optic nerve. Usually, glaucoma will be present in both eyes, although it can be more severe in one.
Glaucoma can lead to sight loss, most commonly in your peripheral vision, meaning the symptoms can initially go unnoticed. Currently about 60.5 million people around the world are affected by glaucoma (Statistics from the Glaucoma Foundation).
Different types of glaucoma
Glaucoma can come in different forms, depending on its cause or symptoms.
Primary open angle glaucoma- This is the most common form of glaucoma. It affects around 1-2% of people over 40, with about half unaware that they have the condition. It becomes more prevalent as you get older, affecting about 10% of over 70s. It’s responsible for 10-12% of all people registered with severe visual impairment in the UK. It usually presents no symptoms in its early stages and the pressure in your eye builds up slowly.
- Primary angle closure glaucoma (or closed angle glaucoma)- This form is more uncommon, and has a rapid onset, normally with sudden and severe pain in the eye.
- Secondary glaucoma- This form of glaucoma is can be caused by an existing eye condition, such as uveitis (inflammation of the eye), an injury or trauma to the eye or as a side effect from a certain medication.
- Normal tension glaucoma- The pressure inside the eye remains normal (between 10-21 mm Hg), although there is damage to the optic nerve. The cause of this is as yet unknown, but could be a result of a weaker optic nerve, unable to withstand the normal eye pressure.
- Childhood glaucoma (also known as congenital glaucoma)- It’s rare, but children can suffer from glaucoma. Very young children who have glaucoma are usually born with an issue in how the eye drains its internal fluids.
Glaucoma causes - who is most at risk?
Anyone of any age, race, or gender can get glaucoma. Although, it is more common in
- People over 70- affects around 10%
- People of African, Caribbean, or Asian descent- People of African descent are 6 to 8 times more likely to go blind from glaucoma than Caucasian people.
- Those with a family history of the condition.
- Ocular hypertension – 9% of people with this condition go on to develop glaucoma, if left untreated for five years.
- Having myopia (short-sightedness) or retinal disease can make it more likely you will go on to have glaucoma. Diabetes may also be a risk factor.
(Statistics from the Glaucoma Research Foundation)
If you have glaucoma, you are unlikely to notice you’re experiencing any symptoms at first. This is because the most common type, primary open angle glaucoma, develops very slowly over a number of years.
Another reason it is difficult to determine if you have glaucoma is because one of the first symptoms is loss of peripheral vision (leading to "tunnel vision"). Peripheral vision is how you see objects on the outskirts of your vision, therefore you don’t rely on it much. This means you’re less likely to notice when it’s failing.
Most forms of glaucoma develop over a period of time, however sudden onset of glaucoma can cause the following symptoms:
- Intense eye pain
- Red eye
- Tenderness around the eyes
- Seeing halos around light sources
- Blurred vision
If you experience these symptoms suddenly, it’s recommended you visit your nearest A&E or eye casualty unit.
Reducing the risk of glaucoma
There is no real known way to prevent glaucoma. However, once it is diagnosed, there are various methods to slow its progression. The earlier the condition is diagnosed, the more effective the treatment will be for slowing down vision loss. Your optician will test for various signs of glaucoma in a standard eye test. You should have a vision check-up at least once every two years or when your optician recommends if sooner
Treatment for glaucoma
There isn’t a cure for glaucoma but there are several ways to bring the pressure in your eyes down to slow its progression. This can be done with eye drops, injections, laser treatment and also surgery. If left untreated, glaucoma can lead to permanent vision loss and although only a small proportion of people end up blind, it really is important to visit your optician regularly to ensure your eyes are healthy on the inside.