TL;DR
If you’re concerned about protecting your sight, it’s important to know the first warning signs of glaucoma to look out for. Early detection is key, and understanding how glaucoma begins can help you act before serious damage occurs.
Glaucoma and its impact on vision
Glaucoma is a group of eye conditions that damage the optic nerve. This nerve sends visual information from your eyes to your brain. When it becomes damaged, blind spots can develop and progress if left untreated.
The most common form is primary open-angle glaucoma. It usually develops slowly over time due to increased pressure in the eye (intraocular pressure). Other types, such as angle-closure glaucoma, can develop more suddenly and are considered medical emergencies.
While glaucoma can affect anyone, your risk increases with age. The condition is more common in people over 60, those with a family history of glaucoma, and people of African, Caribbean or Asian descent.
The first sign of glaucoma is often loss of peripheral vision
The earliest and most common symptom of glaucoma is subtle loss of peripheral (side) vision. This change is usually so gradual that many people are not aware it’s happening.
Peripheral vision is what you see outside your direct line of sight. In the early stages of open-angle glaucoma, this area begins to narrow. Because the central vision remains unaffected at first, daily tasks like reading or recognising faces may seem completely normal.
However, you might start to notice small changes such as:
- Bumping into objects more frequently
- Finding it harder to notice people approaching from the side
- Difficulty navigating dimly lit areas
Since these signs develop slowly, you may unconsciously adapt, making the change even harder to detect without an eye test.
Why early signs of glaucoma often go unnoticed
Glaucoma has been called the silent thief of sight for good reason. The condition damages vision so gradually that you may not experience any pain or discomfort.
In open-angle glaucoma, the pressure in the eye rises slowly over months or years. There is no redness, no soreness, and no change in how your eyes feel. Without noticeable discomfort, it’s easy to believe everything is fine.
This is why many people only discover they have glaucoma during a routine eye examination. By that time, some vision may already be permanently lost. Unlike other health problems, you can’t feel raised eye pressure unless it rises very suddenly, as in angle-closure glaucoma.
What happens during a glaucoma eye test?
Regular eye exams are the only reliable way to catch glaucoma early. During your appointment, the optometrist will carry out a range of checks, which usually include:
- Eye pressure measurement (tonometry): To detect any rise in intraocular pressure.
- Visual field testing: To map your peripheral vision and detect any blind spots.
- Optic nerve examination: Using imaging tools to look for signs of damage.
- OCT scans: To detect structural changes in the nerve before symptoms appear.
These tests are painless and quick. In the UK, eye exams are free for people over 60, and for those at increased risk due to family history or other factors. Regular testing is strongly encouraged every two years, or more often if recommended.
Less common early symptoms in angle-closure glaucoma
Although open-angle glaucoma is the most common, angle-closure glaucoma behaves differently. It develops quickly and requires immediate treatment.
The early symptoms of this type are more obvious and include:
- Sudden blurred vision
- Severe eye pain
- Nausea and vomiting
- Halos around lights
- Eye redness
If you experience any of these signs, you should seek emergency medical help. This form of glaucoma can cause permanent damage within hours if left untreated.
Other risk factors that may signal early glaucoma
While peripheral vision loss is the main early sign, there are other changes that suggest a developing problem. These include:
- Trouble adjusting to low light
- Needing brighter light for reading
- Eyestrain or mild headaches after visual tasks
- Changes in contrast sensitivity
How fast does glaucoma progress?
The rate of progression varies from person to person. Some forms of glaucoma can remain stable for years with the right treatment, while others may advance more quickly.
Primary open-angle glaucoma tends to move slowly, but without intervention, the loss becomes irreversible. Once vision is gone, it cannot be restored.
The key to preserving sight is early detection and ongoing monitoring. If you’re diagnosed early, eye drops or laser treatments can often manage the condition effectively and protect your remaining vision.
How glaucoma is treated after diagnosis
If glaucoma is detected early, treatment usually starts with prescription eye drops. These help reduce pressure within the eye to slow down or stop further damage. Other treatment options include:
- Laser therapy: This improves fluid drainage to reduce pressure.
- Surgery: Reserved for more advanced cases or where other treatments fail.
Treatment is not aimed at restoring lost vision but at preventing additional damage. This is why acting early makes such a difference. In many cases, people with early glaucoma can live full lives with little disruption if treatment is followed closely.
Early detection is always key
The first sign of glaucoma is usually loss of peripheral vision. Because it develops so gradually, you may not realise it’s happening until the damage is done. Carrying out routine eye tests is essential.
If you’re over 40, have a family history of glaucoma, or belong to a higher-risk group, make sure you’re getting tested regularly. The sooner glaucoma is caught, the better your chances of keeping your vision for life.
