Types of Glaucoma

Glaucoma is defined as a group of eye disorders that damages the optic nerve,¹ leading to vision loss and blindness.¹

Glaucoma is usually a result of increased pressure inside the eye,¹ the exact cause of glaucoma is unknown.¹ It may be caused by issues like poor drainage in the eye, a build-up of fluid in the eye, or poor blood supply to the optic nerve.¹

The two main types of glaucoma are described below.²

Primary open-angle glaucoma

Adapted from Marais A, Osush E. 2017. & Shutterstock. ID: 77803252.

This is the most common type of glaucoma.^1,2 It develops slowly and is a lifelong condition.^1,2

Open-angle glaucoma occurs when the eye’s drainage system is clogged or working too slowly, which causes a build-up of fluid and increased pressure in the eye over time.^1,2

The increase in pressure gradually damages the optic nerve, causing vision loss.^1,2 It may eventually lead to blindness.¹

Because it’s slow and painless, open-angle glaucoma often goes undetected until its advanced stages.¹

‘Open-angle’ means that the drainage angle between your iris (the coloured part of your eye) and cornea (the clear dome that covers the front of your eye) is wide and open – which is normal.^3,4

Angle-closure glaucoma

Adapted from Marais A, Osush E. 2017. & Shutterstock. ID: 77803252.

Angle-closure glaucoma occurs when the drainage angle between your iris and cornea becomes too narrow or ‘closed’.^1,2 This blocks the drainage canals and causes a sudden rise in pressure in the eye.^1,2

Angle-closure glaucoma usually develops quickly and should be treated as a medical emergency.^1,2 Symptoms include eye pain, eye redness, nausea, blurred vision and seeing ‘halos’ or coloured rings around lights.¹

Without immediate medical attention, angle-closure glaucoma (also called acute glaucoma or narrow-angle glaucoma) can cause vision loss within just one day of onset.^1,2

Other less common types of glaucoma include:

• Secondary glaucoma: Occurs because of a physical injury or a medical condition.¹
• Congenital glaucoma: Occurs in babies when there is a problem with the development of the eye’s drainage canals.²
• Normal-tension or normal-pressure glaucoma: Occurs when the optic nerve is damaged, although the eye pressure level remains normal. It is not known why this type of glaucoma occurs.^1,2

What does glaucoma look like?

Open-angle glaucoma¹

• This is a slow, painless condition that may not have noticeable symptoms at first.
• Over time, open-angle glaucoma will start to cause loss of peripheral vision (side vision).
• Without treatment, it will advance to central vision loss and blindness.

Angle-closure glaucoma^1,2

• This condition has noticeable symptoms, including eye pain, blurred vision and seeing halos.
• If you experience these symptoms, seek immediate medical treatment.

Glaucoma can be managed with the right treatment.¹ Early detection is important, so make sure you have your eyes tested regularly to check for glaucoma and other eye problems.¹