Types of Glaucoma

The types of glaucoma may include primary open angle glaucoma, primary angle closure glaucoma, normal tension glaucoma, congenital glaucoma and secondary glaucoma. Some of the different types of glaucoma are listed below.

Primary Open Angle Glaucoma: Primary open angle glaucoma can develop gradually without any noticeable symptoms as a result of the eye's drainage system slowly growing inefficient over time.
Primary Angle Closure Glaucoma: Primary angle closure glaucoma can occur when the drainage angle located between the iris and cornea becomes narrow and blocks fluid drainage.
Normal Tension Glaucoma: Normal tension glaucoma occurs when a patient has normal intraocular pressure, but there is still damage to the optic nerve.
Congenital Glaucoma: Congenital glaucoma is a rare form that is present at birth and early childhood, due to the incomplete development of the eye's intraocular fluid drainage system.
Secondary Glaucoma: Secondary glaucoma is a category of different types of glaucoma that occurs as a result of another eye problem or disorder.

1. Primary Open Angle Glaucoma

Primary Open Angle Glaucoma is not caused by another medical condition. According to Glaucoma Australia, open-angle glaucoma is typically caused by high intraocular pressure inside the eye that damages the optic nerve. The high pressure is typically due to an imbalance in the flow of fluid in the eye. There are typically no symptoms for primary open-angle glaucoma, as most patients will not notice any vision changes and will not experience pain. It is considered the most common form of glaucoma in Australia and is typically treated with eye drops that help reduce increased intraocular pressure.

2. Primary Angle Closure Glaucoma

Primary Angle Closure Glaucoma can occur when the iris is physically pushed or moved forward, blocking the drainage angle completely. This hinders the healthy outflow of aqueous humour, according to Glaucoma Australia. Treating the increased ocular pressure may depend on the extent of damage to the trabecular meshwork and angle closure.

3. Normal Tension Glaucoma

Normal-tension Glaucoma is characterised by normal intraocular pressure, but there is still damage to the optic nerve. According to Glaucoma Australia, it is believed that normal-tension glaucoma can stem from a lack of ocular blood flow to the optic nerve, which makes a person more susceptible to developing this type of glaucoma. As with many other types of glaucoma, patients may not typically experience any symptoms, which is why early detection can be very difficult. Normal-tension glaucoma may be treated with eye drops that will lower eye pressure, and surgery or laser treatment may be suggested to slow its progression in an attempt to preserve eyesight.

4. Congenital Glaucoma

Congenital Glaucoma is a rare type of glaucoma that develops at birth and early childhood, due to the improper development of the eye's intraocular fluid drainage system, which causes high eye pressure. According to the National Eye Institute, the symptoms of congenital glaucoma in children include cloudy eyes, sensitivity to light, eyes that are larger than normal and excessive tear production.

5. Secondary Glaucoma

Secondary Glaucoma is a category of different types of glaucoma that is caused by another eye problem or disorder. According to Glaucoma Australia, types of secondary glaucoma include pigmentary glaucoma, related to the iris; neovascular glaucoma, which can develop when the eye does not receive enough blood and oxygen; traumatic glaucoma, caused by a direct injury to the eye; uveitic glaucoma, the result of the eye condition uveitis; and steroid-induced glaucoma, caused by steroid medications. Symptoms are not usually experienced in the early stages, which is why it is recommended to have an eye test at least once every two years so an optometrist can assess for eye diseases and conditions, including glaucoma.

How do Different Types of Glaucoma Compare?

There are many different types of glaucoma, which can affect individuals differently. When comparing some of the different types of glaucoma, the most common form, according to Glaucoma Australia, is open-angle glaucoma. This type is slow-growing and normally detected during a routine standard eye test with an optometrist and can include risk factors such as being over the age of 50, having a family history of glaucoma, and short-sightedness. The type that may urgently require treatment is acute angle-closure glaucoma due to the rapid increase of intraocular pressure.

What is the Difference Between Primary and Secondary Glaucoma?

The difference between primary and secondary glaucoma is their cause. Primary glaucoma can occur without an individual already having an underlying condition, while secondary glaucoma is the consequence of specific triggers that can be identified, such as inflammation, an injury to the eye or tumours.

Do All Types of Glaucoma Require the Same Treatment?

No, all types of glaucoma may not require the same treatment. While most cases may be managed effectively through the use of eye drops, laser treatment or surgery, treatment can differ between patients. It may be important to note that while treatment can help prevent vision loss, it cannot restore sight that is already impaired from glaucoma.

Which Type of Glaucoma is the Most Serious?

The type of glaucoma that may be most serious is acute angle-closure glaucoma. Acute angle-closure glaucoma may be less common but can be a medical emergency and require urgent care. It causes a rapid increase in eye pressure, which can result in vision loss in a shorter span of time, unlike other types, which are slowly progressing.

Which Glaucoma Type Has the Highest Risk of Vision Loss?

The glaucoma type that may have the highest risk of vision loss is acute angle-closure glaucoma, as it can cause a sudden spike in intraocular pressure and lead to vision loss in a matter of hours. Other forms of glaucoma, such as primary open-angle glaucoma, are considered more common and may take longer to progress.

Can Early Diagnosis Help Prevent Blindness From Any Type of Glaucoma?

Yes, early diagnosis may help prevent blindness from any type of glaucoma. However, it is important to note that vision impairment that is already present cannot be restored. Having regular eye tests can help with early detection and allow treatments to effectively delay progression and reduce eye pressure.

How do Eye Doctors Diagnose Different Types of Glaucoma?

Eye doctors can diagnose different types of glaucoma through an eye test. An optometrist or ophthalmologist can identify each form by assessing the optic nerve, other structures in the eye, and pressure levels. There are several steps as part of a routine eye test that can help eye care professionals examine all important regions of the eye. In Australia, ophthalmologists are the only eye care professionals who are considered eye doctors; however, optometrists are qualified and trained to diagnose eye conditions including glaucoma.

What Eye Tests Help Identify the Type?

The eye tests that can help identify the type of glaucoma can include tonometry, gonioscopy, visual field test, optical coherence tomography and ophthalmoscopy. The eye tests that can help identify the type are listed below.

Tonometry: A tonometry test can help with diagnosing glaucoma as it measures the pressure in your eyes, known as intraocular pressure.
Gonioscopy: A gonioscopy is a test that examines how well the drainage system in the eye works.
Visual Field Test: A visual field test assesses the condition and quality of one's peripheral vision. As peripheral vision is the area of sight affected by glaucoma, a visual field test is important in helping to diagnose glaucoma.
Optical Coherence Tomography: Optical coherence works by using near-infrared light to illuminate and assess how much light is subsequently reflected off the retina and optic nerve.
Ophthalmoscopy: Ophthalmoscopy helps eye care professionals to examine the interior structures of the eye such as the optic nerve and retina.

How is Each Type of Glaucoma Treated?

Each type of glaucoma may be treated with eye drops, laser therapy and surgery. The different treatment options for each type of glaucoma are listed below.

Eye Drops: Eye drops are typically the first line of treatment for glaucoma and work by reducing intraocular pressure by either reducing the amount of fluid your eye produces or improving fluid drainage.
Laser Therapy: Laser therapy for each glaucoma type can help aqueous humour flow better and also help this fluid drain more effectively within the eye. This treatment is performed by an ophthalmologist.
Surgery: Surgery is used to treat each glaucoma type when the condition is unable to be helped by other forms of treatment such as medication, eye drops and laser treatment. Common eye surgeries for glaucoma include Trabeculectomy and Glaucoma Drainage Devices.

Which Treatments Work Best for Different Types?

The treatments that can work best for different types will typically include the usual options, such as eye drops, laser therapy and surgery. The exact treatment that will work best for the different types will depend on the severity and stage of the patient's condition. It is important to note that it may be difficult to state which particular treatment is the most suitable for every form, as treatment varies between individuals.

Do All Types of Glaucoma Require Surgery?

No, all types of glaucoma do not require surgery. Certain types or cases of glaucoma may only need surgery when eye drops and laser therapy are not effective on the condition.

What Risk Factors Increase the Chance of Developing Glaucoma?

The risk factors that may increase the chance of developing glaucoma include having a family history of glaucoma, being over the age of 50, having diabetes, being short- or long-sighted, on long-term use of steroid medication, having had an eye operation or eye injury and having high blood pressure.

Mindmap of the different glaucoma risk factors.

Can Family History Increase Your Risk?

Yes, having a family history of glaucoma can increase your risk of developing glaucoma. According to Glaucoma Australia, first-degree relatives, which include parents, siblings and children, have a higher risk of developing glaucoma. This is why it is important to let your optometrist know and ensure you get regular eye tests to help with early detection and timely treatment.