Glaucoma is often called the “silent thief of sight” because it can damage your vision without causing noticeable symptoms in its early stages. Many people assume that a serious eye condition will produce obvious warning signs, but glaucoma often develops gradually, and significant, irreversible vision loss may occur before a person realises anything is wrong.
So, does glaucoma have symptoms? The honest answer is sometimes—but often not until the disease has already progressed.
In this guide, we’ll explain the early signs of glaucoma, the symptoms associated with different types of glaucoma, who is most at risk, and why regular comprehensive eye examinations are the best way to protect your eyesight.
What Is Glaucoma?
Glaucoma is a group of eye diseases that damage the optic nerve, which carries visual information from the eye to the brain. While elevated intraocular pressure (IOP) is the most significant risk factor, glaucoma can also develop in people with normal eye pressure.
The eye continually produces a clear fluid called aqueous humour, which normally drains through the eye’s natural drainage system. If this fluid does not drain efficiently, pressure inside the eye may increase, placing stress on the optic nerve. Over time, this damage can lead to permanent vision loss and, if left untreated, may eventually result in blindness.
There are two main types of glaucoma, and their symptoms are very different.
Open-Angle Glaucoma: The Silent Thief of Sight
Open-angle glaucoma is by far the most common type of glaucoma. Unfortunately, it is also the type most likely to develop without any noticeable symptoms.
In its early stages, open-angle glaucoma does not usually cause pain or obvious changes in vision. Pressure may build slowly, and the optic nerve gradually becomes damaged. Because our eyes naturally compensate for early blind spots, many people don’t notice a problem until substantial optic nerve damage has already occurred.
When symptoms do develop, they may include:
- Gradual loss of peripheral (side) vision
- Tunnel vision in advanced stages
- Difficulty adjusting to low-light conditions
- Blurred or patchy areas within your field of vision
Unfortunately, by the time these symptoms become noticeable, permanent vision loss has often already occurred. This is why open-angle glaucoma is so dangerous and why regular eye examinations are essential.
Angle-Closure Glaucoma: A Medical Emergency
Angle-closure glaucoma is much less common but develops suddenly and requires urgent medical attention.
This occurs when the iris blocks the eye’s drainage angle, causing a rapid increase in eye pressure known as an acute angle-closure attack.
Unlike open-angle glaucoma, this condition produces obvious symptoms that should never be ignored.
Symptoms include:
- Severe, sudden eye pain
- Severe headache
- Blurred vision or seeing halos around lights
- Nausea and vomiting
- Redness of the affected eye
- Sudden loss of vision
If you or someone you know experiences these symptoms, seek immediate medical attention or present to your nearest emergency department. Permanent vision loss can occur within hours if treatment is delayed.
Other Types of Glaucoma
There are several other forms of glaucoma and related conditions worth knowing about.
Normal-tension glaucoma causes optic nerve damage despite normal eye pressure and usually develops without early symptoms.
Ocular hypertension refers to higher-than-normal eye pressure without evidence of optic nerve damage. Although glaucoma has not yet developed, these individuals have an increased risk and should be monitored regularly.
People with pigment dispersion syndrome or pigmentary glaucoma may occasionally notice blurred vision or halos around lights following vigorous exercise due to pigment temporarily blocking the eye’s drainage system.
Who Is Most at Risk?
Certain groups have a higher risk of developing glaucoma and should have regular comprehensive eye examinations.
Risk factors include:
- Being over 40 years of age
- A family history of glaucoma
- Black African, Black Caribbean or East Asian ancestry
- Diabetes
- High short-sightedness (myopia) or long-sightedness (hyperopia)
- Previous eye injuries
- Long-term corticosteroid use
Why Regular Eye Examinations Matter More Than Symptoms
The most common form of glaucoma rarely causes symptoms until permanent damage has already occurred. Waiting until you notice changes in your vision may mean valuable treatment opportunities have been lost.
Regular eye examinations allow your optometrist or ophthalmologist to detect glaucoma before symptoms develop.
A comprehensive glaucoma assessment may include:
- Measurement of intraocular pressure (tonometry)
- Examination of the optic nerve
- Visual field testing to detect early peripheral vision loss
- Optical coherence tomography (OCT) scanning of the optic nerve
It’s also important to remember that not everyone with elevated eye pressure develops glaucoma, and some people develop glaucoma despite having normal eye pressure. This is why a comprehensive eye examination is far more valuable than relying on eye pressure measurements alone.
In Australia, adults should have regular comprehensive eye examinations, with the frequency depending on their age and individual risk factors. People over 40—particularly those with a family history of glaucoma or other risk factors—may require more frequent examinations as recommended by their optometrist or ophthalmologist.
Can Glaucoma Be Treated?
Vision already lost from glaucoma cannot be restored. However, if glaucoma is detected early, treatment can significantly slow or prevent further damage.
Treatment options may include:
- Prescription eye drops to lower eye pressure
- Laser treatment to improve fluid drainage
- Surgical procedures for more advanced glaucoma
Early diagnosis remains the most effective way to preserve vision.
The Bottom Line
Does glaucoma have symptoms? In its most common form, usually not—at least not until irreversible damage has already occurred.
While acute angle-closure glaucoma causes sudden symptoms that require emergency treatment, open-angle glaucoma often develops silently over many years.
Regular comprehensive eye examinations are the best way to detect glaucoma early, before vision loss occurs. If you have concerns about your eye health or are at increased risk of glaucoma, speak with your optometrist or book an appointment with an ophthalmologist for a comprehensive assessment.
Frequently Asked Questions
1. What are the first signs of glaucoma?
Open-angle glaucoma usually has no noticeable symptoms in its early stages. As the disease progresses, people may experience gradual loss of peripheral vision, difficulty seeing in low light, and patchy blind spots. In contrast, angle-closure glaucoma causes sudden eye pain, blurred vision, halos around lights, headache, nausea and vomiting.
2. Can glaucoma cause sudden blindness?
Most glaucoma develops slowly over many years. However, an acute angle-closure glaucoma attack can cause rapid and permanent vision loss within hours if left untreated and is considered a medical emergency.
3. At what age should I start getting checked for glaucoma?
Adults over 40 should have regular comprehensive eye examinations, particularly if they have a family history of glaucoma or other risk factors. Your optometrist or ophthalmologist can recommend how often you should be assessed based on your individual risk.
4. Is glaucoma hereditary?
Yes. Having a close family member with glaucoma significantly increases your risk of developing the disease. Family history is an important part of every comprehensive eye examination.
5. Can glaucoma be cured?
There is currently no cure for glaucoma, and vision that has already been lost cannot be restored. However, early diagnosis and appropriate treatment—including eye drops, laser therapy or surgery—can often prevent or significantly slow further vision loss.