Understanding the Different Types of Glaucoma

Amisha Jain
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Dr. Kaushal

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Glaucoma is an eye condition that causes damage to the optic nerve.

Usually, Glaucoma is a result of high eye pressure for a considerable amount of time.

But it can also happen with normal eye pressure due to other factors.

According to the WHO, Glaucoma is one of the leading causes of blindness in the world.

Therefore, knowing the type of Glaucoma affecting you becomes essential for you.

It helps to identify the underlying cause of the condition and follow the correct course of treatment.

Discussed here are the various types of Glaucoma.

Primary Glaucomas

Some types of Glaucoma are caused by a medical condition or disease.

But sometimes, it can be due to reasons other than a condition or disease.

These are called primary Glaucomas.

Following are the various types of Primary Glaucoma.

Open-angle Glaucoma

Primary Open-Angle Glaucoma (POAG), also called open-angle Glaucoma, is a lifelong condition.

It accounts for about 90% of all Glaucoma cases, affecting nearly three million Americans.

In POAG, there is a rise in intraocular pressure.

This is because of insufficient fluid drainage from the eye.

The entrance to these canals is clear, but there is clogging further inside.

There are no symptoms or early warning signs of this condition.

Over time, the optic nerve is damaged due to this high intraocular pressure.

Usually, people with Open-angle Glaucoma respond well to treatments, especially if caught in the earlier stage of the condition.

Angle-closure Glaucoma

In this type of Glaucoma, there is a bulge in the iris.

When the pupil enlarges too quickly or too much, the edges of the iris bunch up over the drainage canals.

This bulging iris blocks the eye’s drainage angle either wholly or partially.

As a result, the aqueous humor that maintains the eye pressure does not circulate properly and increases the eye pressure.

Normal-tension Glaucoma

Normal-Tension Glaucoma (NTG) is a form of POAG.

It is also called normal-pressure Glaucoma.

Under this condition, the eye pressure usually remains within the normal range, but there is damage to the optical nerve.

Patients with Normal-tension Glaucoma face central vision issues.

Factors such as insufficient blood flow to the optic nerve and structural weakness of the optic nerve tissue play a role in NTG.

Childhood Glaucoma

eye checkupSource: Brazo_de_Hierro
eye checkup

Childhood Glaucoma affects one of every 10,000 births in the US, of which around 80% of cases are diagnosed in the first year of life. 

Glaucoma in childhood can be divided according to the age of onset of the condition.

  • Congenital Glaucoma has existed since birth.
  • Infantile Glaucoma develops within the first 24 months after the birth of a child.
  • Juvenile Glaucoma develops after three years of age.
Childhood Glaucoma could either be primary or secondary congenital Glaucoma.
Most cases of primary congenital Glaucoma are sporadic.
Secondary childhood Glaucoma is linked to eye problems that were present at birth.

Secondary Glaucomas

Glaucoma that is caused by or linked to another disease or condition is called secondary Glaucoma.

Some types of secondary Glaucoma are listed below.

Neovascular Glaucoma

Neovascular Glaucoma (NVG) is a type of secondary Glaucoma.

It is associated with disorders that restrict blood flow to the retina.

This reduction in blood flow leads to the production of a growth factor causing the formation of new blood vessels.

When these vessels form over the drainage channels, they block the flow of aqueous humor.

This results in increased intraocular pressure, which might damage the optic nerve.

NVG is prevalent nowadays due to the increasing cases of diabetes.

Most of the NVG cases are attributed to

  • Ischemic central retinal vein occlusion (CRVO)
  • Proliferative diabetic retinopathy (PDR)
  • Ocular ischemic syndrome (OIS)

Pigmentary Glaucoma

Also called pigment dispersion Glaucoma, it is a type of secondary open-angle Glaucoma.

Pigment Dispersion Syndrome (PDS) is a risk factor for developing Glaucoma. 

An elderly man facing issues with GlaucomaSource: Panupong_Piewkleng_from_Getty_Images
Glaucoma patient

It is characterized by the dispersion of the pigment of the iris, which deposits in the eye’s drainage system. 

PDS might cause permanent damage to the drainage canal.

This damage leads to high eye pressure, which might cause damage to the optic nerve and lead to Glaucoma.

Exfoliation Glaucoma

Exfoliation Glaucoma is a secondary form of open-angle Glaucoma caused as a result of exfoliation syndrome.

Exfoliation syndrome is a systemic condition caused due to abnormal deposition of protein in the drainage channel and other parts of the eye.

It is the most common secondary type of open-angle Glaucoma that is identifiable worldwide.

Exfoliation Glaucoma progresses faster than POAG and causes higher eye pressure and hence requires regular eye examination.

Uveitic Glaucoma

People with Uveitis suffer a risk of uveitic Glaucoma.

Uveitis causes eye inflammation because your immune system is fighting an infection.

Uveitis can cause obstruction leading to a decreased outflow of aqueous humor.

This leads to an increase in intraocular pressure.

Sometimes, inflammation might cause scar tissue in the longer run. This might also lead to obstruction of fluid drainage, causing elevated eye pressure.

The elevated eye pressure poses a risk of Glaucoma if left untreated.

Traumatic Glaucoma

Traumatic Glaucoma is a kind of secondary eye trauma caused by the various factors associated with injury to the eye.

All kinds of eye trauma have the potential to cause an increase in the eye pressure in the affected eye in some way.

It can be blunt trauma (injuries that bruise the eye) or injuries that penetrate the eye.

Blunt trauma

When blunt trauma occurs, the excess blood, plasma, and debris may accumulate and clog the drainage channel.

This might cause an increase in eye pressure leading to damage to the optic nerve.

In some instances, the damaged drainage canals can build up scarring in the eye. This scarring also obstructs the fluid flow and might lead to Glaucoma.

Penetrating injury

Traumatic Glaucoma can also be due to a penetrating injury to the eye, such as one caused by a sharp instrument.

In such cases, the eye pressure is usually lower right after an injury.

But as soon as the wound is closed, the tissues inside the eye might get swollen and irritated.

Bleeding can occur as well, leading to a rise in eye pressure.

Recommended Reading:
To know about Glaucoma treatment options, read Managing Glaucoma: Understanding the Glaucoma Treatment Options.


Glaucoma is a long-term and progressive eye condition.

It could be primary or secondary based on whether or not any specific underlying condition has caused it.

By figuring out the type of Glaucoma, your doctor can best guide you through the treatment to manage the condition.

This will not only prevent your condition from deteriorating but might also prevent loss of vision.

You should, therefore, consult your ophthalmologist for regular checkups to maintain healthy eyes.

Frequently Asked Questions

How many types of Glaucoma are there?

According to the National Eye Institute, there are four major primary Glaucoma types and five secondary Glaucoma types. Among these, the two main types of Glaucoma include Open-Angle and Angle-Closure.

What are the four types of Glaucoma?

The four types of primary Glaucoma include Open-angle, angle-closure, normal-tension, and childhood Glaucoma.

Which is the most common type of Glaucoma?

Primary open-angle Glaucoma, also called open-angle Glaucoma, is the most common type of Glaucoma. It accounts for 90% of all Glaucoma cases, says Cleveland Clinic.

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