Eye Health

Updated 15 February 2016

Glaucoma: a silent but devastating eye condition

4 in 50 South Africans over the age of 40 suffer from glaucoma, the 3rd leading cause of blindness globally. This is what you need to know about this silent condition.


Despite how common glaucoma is, many people do not know what it is, let alone know the signs of this silent but dangerous condition. 

Glaucoma is a group of eye diseases which affects approximately 70 million people and a further 4.5 million are blind as a result of the condition, according to the World Glaucoma Week website.

Sadly about 50% of people don’t even know that they have the disease – this percentage is as high as 90% in developing countries, according to the South African Glaucoma Society. It is estimated that 4 in 50 South Africans over the age of 4 suffer from the condition. Also called “the blinding disease” or “thief of sight”, glaucoma develops without warning or obvious symptoms.  

What is glaucoma?

In a nutshell, glaucoma is an eye disease that involves damage to the optic nerve.

This nerve sends visual signals to the brain, where they are processed into what you “see”. No one knows what causes glaucoma, but pressure build-up in the eye has been proven to be a major risk factor.

When the pressure in the eye gets too high, the optic nerve can get damaged. This damage causes some signals from the eye not to reach the brain. The result is that you can’t ‘see” everything your eye sees.

This leads to reduced visual field, and if not managed, may lead to blindness.


As there is no cure yet for glaucoma, early detection is essential to preserve your eye-sight and diagnosis is the first step – know your risk factors.

The family connection

One of the biggest risk factors for glaucoma is your family history. The most common type of glaucoma, primary open-angle glaucoma, is hereditary.

If members of your immediate family have glaucoma, you are at a much higher risk than the rest of the population.

The statistics speak for themselves: A person who has a parent with glaucoma has a five times greater risk of developing the disease, and should you have a sibling with glaucoma, your risk increases nine fold.

Ethnic background also plays a part in determining your risk factors – glaucoma is six to eight times more common in the black African population than in the European population.

Other glaucoma risks factors include ageing, nearsightedness, previous eye injuries, steroid use, and health conditions such as cardiovascular disorders and diabetes.

Though the cause of glaucoma is still unknown and there is no cure yet, the condition can be managed well with treatment and regular check-ups. Early diagnosis and treatment is also very effective in delaying or preventing disease progression.

Read: High blood pressure boosts glaucoma risk

What are the symptoms?

At first, there are no symptoms. Vision stays normal, and there is no pain. However, as the disease progresses, a person with glaucoma may notice their vision gradually failing.

“Glaucoma can develop in one or both eyes," says Dr Ellen Ancker, Cape Town ophthalmologist and director of the World Glaucoma Patient Association.

“Objects in front may still be seen clearly, but objects to the side may be missed. Without treatment, people with glaucoma will slowly lose their peripheral (side) vision."

They seem to be looking through a tunnel. "Over time, straight-ahead vision may decrease until no vision remains."

The South African Glaucoma Society recommends that individuals who fall into the risk groups for glaucoma, or who experience symptoms such as described above, see an ophthalmologist to determine how frequently their eyes should be examined.

“If someone in your family has glaucoma, you should have your eyes tested regularly. This is especially important if the affected relative was under 40 years of age when the glaucoma was discovered. Generally, if you are over 40, you should have your eyes tested every two years, and every year once you are over the age of 60.”

Read: Glaucoma explained

How is it treated?

According to Ancker, once a patient has been diagnosed with glaucoma, they have to go on life-long medication - often in the form of medicated eye drops. 

“Glaucoma is a chronic disease which requires patients to use medication on a daily basis - regular use of the medication can help retain their eye sight."

eye drops

"It is also really important to go for regular checkups and have a good relationship with your doctor. 

You must be able to trust your doctor and notify him or her as soon as there are any changes in your vision or when you are experiencing any problems.”

If treatment with one or more medications is unsuccessful, your ophthalmologist can also recommend surgery. “However, this is not a first option,” says Ancker, “as there is a greater danger of infection and it can lead to cataracts in older patients.”

Read more:

Breakthrough may improve glaucoma treatment

The Pill linked to higher glaucoma risk

Benefits of glaucoma screening questioned

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Images: Doctor helps the patient by giving eye dropsGlaucomaApplanation tonometry test for eye pressure all from Shutterstock


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Megan Goodman qualified as an optometrist from the University of Johannesburg. She has recently completed a Masters degree in Clinical Epidemiology at Stellenbosch University. She has a keen interest in ocular pathology and evidence based medicine as well as contact lenses.

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