What are the different types of glaucoma?
Glaucoma is a group of eye conditions that damage the optic nerve—the vital connection between the eye and the brain—typically due to increased pressure within the eye. It is one of the leading causes of irreversible blindness worldwide. Understanding the different types of glaucoma is crucial for early diagnosis, timely intervention, and effective long-term management.
In this blog, we will explore the main types of glaucoma, how they differ, along with their common symptoms and treatment options.
1. Primary Open-Angle Glaucoma (POAG)
What is it?
This is the most common type of glaucoma, especially in adults over the age of 40. It develops slowly over time and is often called the “silent thief of sight” because it typically has no early symptoms.
How it happens:
The drainage angle in the eye remains open, but the trabecular meshwork (the drainage system) becomes less efficient. As a result, intraocular pressure (IOP) gradually increases, damaging the optic nerve.
Symptoms:
- Usually none in the early stages.
- Gradual loss of peripheral (side) vision.
- Advanced cases can lead to tunnel vision and blindness.
Treatment:
- Eye drops to reduce IOP.
- Laser therapy. (such as SLT – Selective Laser Trabeculoplasty)
- Surgery in more advanced cases.
2. Angle-Closure Glaucoma (also known as Narrow-Angle Glaucoma)
What is it?
This form of glaucoma occurs when the drainage angle between the iris and cornea closes or becomes blocked, preventing fluid from draining properly. It can develop suddenly (acute) or gradually (chronic).
Acute Angle-Closure Glaucoma is a medical emergency.
Symptoms of acute attack:
- Severe eye pain.
- Blurred vision.
- Halos around lights.
- Red eye.
- Headache and nausea.
Treatment:
- Immediate treatment with medications to reduce eye pressure.
- Laser iridotomy. (creating a small hole in the iris to open the drainage angle)
- Surgery may be needed in some cases.
3. Normal-Tension Glaucoma (NTG)
What is it?
This type of glaucoma occurs even though eye pressure remains within the normal range. The optic nerve is still damaged, likely due to poor blood flow or a particularly sensitive optic nerve.
Who is at risk?
- People with a family history of NTG.
- Individuals with low blood pressure or circulatory problems.
Symptoms:
- Similar to POAG, with peripheral vision loss.
- Often diagnosed during routine eye exams.
Treatment:
- Lowering IOP further with medications or laser.
- Monitoring with regular eye scans and visual field tests.
4. Congenital Glaucoma (Childhood Glaucoma)
What is it?
A rare form that occurs in infants or young children, usually due to a developmental issue in the eye’s drainage system.
Symptoms:
- Enlarged, cloudy cornea.
- Excessive tearing.
- Sensitivity to light.
- Vision problems as the child grows.
Treatment:
- Surgery is usually required to correct the drainage issue.
- Early diagnosis is critical to prevent vision loss.
5. Secondary Glaucoma
What is it?
Secondary glaucoma develops as a result of another medical condition or injury. Causes may include:
- Eye trauma.
- Inflammation (Uveitis)
- Steroid use.
- Advanced cataracts or retinal diseases.
Types of secondary glaucoma:
- Neovascular glaucoma: from abnormal blood vessels, often due to diabetes or retinal vein occlusion.
- Pigmentary glaucoma: from pigment granules clogging the drainage system.
- Pseudoexfoliation glaucoma: from protein-like material peeling off the lens.
Treatment:
- Depends on the underlying cause.
- Eye drops, laser, or surgical treatment may be necessary.
6. Exfoliative (Pseudoexfoliation) Glaucoma
What is it?
This is a form of secondary open-angle glaucoma, associated with a flaky, dandruff-like material that accumulates on the lens and other parts of the eye.
Symptoms:
- Often no early signs.
- Gradual visual field loss.
Treatment:
- More aggressive than POAG as the pressure tends to be higher.
- Eye drops, laser, and surgery.
How is glaucoma diagnosed?
At Clarity Eye Surgeons, glaucoma diagnosis involves a combination of tests:
- Eye pressure measurement. (tonometry)
- Visual field testing to assess peripheral vision loss.
- Optic nerve imaging. (OCT scan)
- Gonioscopy to evaluate the drainage angle.
- Corneal thickness measurement. (pachymetry)
Early detection and ongoing monitoring are crucial to preserving vision.
Conclusion
Glaucoma can be silent, but its impact on vision is profound. The good news is that with early diagnosis and timely treatment, vision loss can be slowed or even prevented. If you are over 40, have a family history of glaucoma, or are experiencing any vision changes, it is important to have a comprehensive eye exam.
At Clarity Eye Surgeons in Canberra, we offer expert care, advanced diagnostic tools, and a personalised treatment approach to manage all types of glaucoma. Book an appointment with our experienced ophthalmologists to protect your vision today.
Author bio
Dr Parth Shah is a director and principal ophthalmologist at Clarity Eye Surgeons in Canberra. With extensive training and experience, he is renowned for his expertise in the field. Dr Shah is dedicated not only to performing successful surgeries but also to patient education. His compassionate approach, combined with technical proficiency, has earned him the trust and gratitude of countless patients. He is a true advocate for eye health and a trusted name in the Canberra ophthalmology community.
FAQs
No, glaucoma cannot be cured, but it can be managed effectively with early diagnosis and treatment. The goal is to slow or stop further damage to the optic nerve.
If you are over 40 or have risk factors like family history, diabetes, or high eye pressure, it is recommended to have a comprehensive eye exam every 1–2 years.
Yes, a family history of glaucoma increases your risk. First-degree relatives of glaucoma patients should have regular eye exams starting earlier in life.
Healthy diet, regular exercise, stress management, avoiding smoking, and keeping systemic conditions (like blood pressure and diabetes) under control can support eye health.
It depends on the severity of your vision loss. Many people with early-stage glaucoma can drive safely. However, advanced cases may impair peripheral vision, making driving unsafe.
No. As in Normal-Tension Glaucoma, damage to the optic nerve can occur even with normal eye pressure.
Most types, like POAG, are painless. However, acute angle-closure glaucoma causes sudden, severe eye pain and is an emergency.
Other blogs related to Eye Conditions
Double vision in children: What parents should know
Double vision in children: What parents should know Double vision, medically called diplopia, occurs when a child sees two images of a single object instead
Glaucoma: What it is, Symptoms, Causes, Types & Treatment
Glaucoma: What it is, Symptoms, Causes, Types & Treatment Glaucoma is often called the “silent thief of sight” because it can damage your vision gradually,
Living with wet macular degeneration: Treatment options and lifestyle tips
Living with wet macular degeneration: Treatment options and lifestyle tips Wet macular degeneration, also known as neovascular age-related macular degeneration (AMD), is a chronic eye
Retinal detachment: Early signs you should never ignore
Retinal detachment: Early signs you should never ignore Your eyes are extraordinary organs that allow you to experience the world in vivid colour, detail, and
Vitrectomy: What you need to know
Vitrectomy: What you need to know Vitrectomy is a specialised eye surgery performed to treat a range of disorders affecting the retina and vitreous —
Diabetes and your eyes: What you need to know
Diabetes and your eyes: What you need to know Diabetes is a chronic condition that affects how your body regulates blood sugar (glucose). While most
Nystagmus: Symptoms, Causes, and Treatments
Nystagmus: Symptoms, Causes, and Treatments Nystagmus is a condition in which the eyes make uncontrolled, repetitive movements. These movements can be slow or fast, side-to-side
What to know about blurry vision and diabetes?
What to know about blurry vision and diabetes? Blurry vision is a common and often early symptom of diabetes. If you or someone you know
Chalazion surgery: When is it necessary and What to expect
Chalazion surgery: When is it necessary and What to expect A chalazion is a common eyelid condition that can lead to discomfort, swelling, and cosmetic
Are prescription glasses effective for treating lazy eye?
Are prescription glasses effective for treating lazy eye? Lazy eye, also known as amblyopia, is a common vision problem in children, affecting a small percentage
Dry Eye Syndrome: Symptoms, Causes & Treatment
Dry Eye Syndrome: Symptoms, Causes & Treatment Do your eyes often feel dry, irritated, or fatigued? You might be experiencing Dry Eye Syndrome (DES)—a common
The Relationship Between Allergies and Eye Health in Children
The Relationship Between Allergies and Eye Health in Children Allergies are a prevalent concern among children and can significantly impact their quality of life. While
Understanding Astigmatism: Symptoms, Causes, Diagnosis, Treatment Options & Prevention
Understanding Astigmatism: Symptoms, Causes, Diagnosis, Treatment Options & Prevention What is Astigmatism? Astigmatism is a common eye condition that affects how your eye focuses light.
Understanding Retinal Detachment: Causes, Symptoms, Diagnosis and Treatment
Understanding Retinal Detachment: Causes, Symptoms, Diagnosis and Treatment As the principal ophthalmologist at Clarity Eye Surgeons, Dr Parth Shah is passionate about educating our patients