Glaucoma – Causes, symptoms and treatment
What is glaucoma?
Glaucoma is a progressive eye condition that damages the optic nerve, which connects the eyes to the brain. In most cases, this is caused by fluid build-up in your eye, leading to increased intraocular pressure.
There are different types of glaucoma, which develop over a varying amount of time, from a few days to several years. However, all types of glaucoma can lead to loss of vision if left untreated. Early detection and careful treatment can slow the condition from progressing and cause irreversible sight loss.
Types of glaucoma
There are several types of glaucoma, but most optometrists define the two main groups as open-angle glaucoma and angle-closure glaucoma.
Open-angle glaucoma is a chronic form of glaucoma that develops gradually. You may not feel any pain or notice vision changes at first as it affects the peripheral vision.
This type of glaucoma typically develops slowly over several years, where the fluid in the eye builds up gradually and damages the optic nerve. Because it is not accompanied by severe symptoms in the early stages, it may only be detected by your optometrist. Open-angle glaucoma is usually managed by prescribed eye drops, and in some cases, surgery may be required.
Angle-closure glaucoma is less common but develops rapidly and calls for immediate action. This type of glaucoma is caused when the pressure inside the eye suddenly increases, resulting in sudden eye pain, red eyes, hazy vision and halos around lights.
If you notice any sudden symptoms, you should see your optometrist immediately for an emergency appointment. Acute angle-closure glaucoma can be treated through eye surgery.
Other types of Glaucoma
Normal-Tension Glaucoma (NTG)
Also known as low-tension glaucoma, Normal-tension glaucoma (NTG) is very similar to primary open-angle glaucoma except that damage to the optic nerve occurs even though eye pressure is not elevated.
An existing eye condition, such as uveitis or an injury/trauma to the eye can cause this form of glaucoma.
A rare type that typically occurs in very young children and is caused by an abnormality in how the eye drains internal fluids.
Who is at risk of glaucoma?
Almost anyone can develop this condition; however, it is more common in:
- People aged over 60
- People with ocular hypertension (high pressure in the eye)
- A family with a history of the condition
- People of African, Caribbean, or Asian descent
Causes of glaucoma
Most types of glaucoma are caused when there are issues with the fluid inside the eye. Either too much fluid is being produced or the fluid inside the eye cannot drain efficiently, which causes pressure to build up. If the pressure increases significantly, it affects the optic nerve, which may result in changes to your vision, such as loss of peripheral vision, and halos around lights, and can even lead to complete vision loss.
Certain medications can increase your risks of glaucoma, and you are more likely to be at risk when you are older, have a family history of glaucoma or are of a particular ethnicity.
Some medications may have increased fluid build-up as one of the side effects and are, therefore, more likely to cause glaucoma. One example of this is steroids, such as corticosteroids, which can raise the pressure inside the eyes, increasing the risk of open-angle glaucoma.
Type 1 and type 2 diabetes patients are generally at risk of developing diabetic retinopathy, and with this comes an increased risk of developing glaucoma. The eye condition retinopathy can cause an irregularly high growth of blood vessels, which may block the drainage of the fluid inside the eye, leading to glaucoma.
If one of your parents or siblings has glaucoma, inform your optometrist of this during your routine eye exams. Most cases of glaucoma are inherited.
Glaucoma typically develops when you are older, after the age of 60. However, there are some rare cases in which glaucoma can start to progress at a younger age.
Those of African, Asian or Caribbean descent are more likely to develop glaucoma.
Symptoms of glaucoma
The common form, open-angle glaucoma, does not start with any symptoms, as it progresses slowly over the years. If you do notice any symptoms, however, the most noticeable ones are usually the following:
From a tenderness of the areas around your eyes to severe pain and red eyes, lasting eye pain is usually one of the signs of glaucoma.
Sudden vision changes
The ways in which glaucoma affects your vision can vary, from general hazy vision to limited peripheral vision and halos when looking at light sources. In advanced stages of glaucoma, you may also experience tunnel vision, in which your visual field is constricted considerably.
Nausea and vomiting
For some people, glaucoma may cause nausea and vomiting, often alongside a headache. This is more likely with closed-angle glaucoma.
Can I avoid glaucoma?
Unfortunately, there is no definitive way to prevent glaucoma. However, once diagnosed, there are various methods that can be carried out to slow progression. The earlier that the condition is diagnosed, the more effective treatment can be.
Standard eye tests will check for signs of glaucoma, and it's recommended to have a vision check-up at least once every two years (or sooner, depending on your optician’s advice).
Treatment options for glaucoma
If glaucoma is left untreated, it can lead to complete loss of vision. An early diagnosis can ensure that you get the correct treatment to avoid this.
Medical treatment options for glaucoma are generally administered in the form of various eye drops.
The correct eye drop medication differs depending on each individual case of glaucoma and how it affects your eyes. Glaucoma treatment is not a generic type of medical eye drop but rather needs to differ for everyone’s eye health and what their bodies and eyes respond to. One example can be beta blockers, which are used to decrease fluid production in those with open-angle glaucoma; though effective for some it is not a suitable option for those taking beta blockers systemically for conditions such as high blood pressure.
Glaucoma can be managed through medication. However, if you have glaucoma, you will likely take medication for the rest of your life.
Different types of surgery can be used to drain the excess fluid out of the eye, which reduces the pressure. Laser therapy surgery can be an option for some patients with open-angle glaucoma, while the surgical instalments of drainage tubes may work better for others.
Any surgical procedure requires follow-up appointments, and you may need to have the surgery more than once if the pressure in your eye rises again.
Can glaucoma be cured?
Unfortunately, glaucoma is an eye condition that cannot be cured, no matter which type of glaucoma you might have. Any changes that have already affected and damaged your optic nerve are non-reversible. However, proper management going forward can slow the progression of glaucoma and reduce the risk of complete vision loss.
How long can you go without treatment before vision loss?
If open-angle glaucoma is left untreated for several years, it will eventually lead to vision loss. However, early detection by your optometrist, followed by carefully managed treatment typically ensures that the progression of the disease is slowed down as much as possible.
With angle-closure glaucoma, you will need to see an eye specialist immediately to avoid an irreparable loss of your vision, as soon as you recognise the symptoms.