What is Glaucoma?

Glaucoma is a group of diseases that damage the eye’s optic nerve and can result in vision loss and blindness. There are several types of glaucoma, however, the two most common are primary open angle glaucoma which is slow and silent in onset, and angle closure glaucoma which is less common and tends to be more acute and painful.

Why should I be aware of glaucoma?

As the effect of open angle glaucoma is a silent, painless, gradual loss of peripheral vision at first, one does not notice the early phase of disease before it is too late. Central vision and the ability to see small detail and print is not affected at first but if untreated, the loss of vision gradually progress to leave only a small central area of vision. In severe cases the eye nerve loses its function and all vision is irreversibly lost.

Why should I have frequent assessments for glaucoma?

Because of the slow silent start of loss in the peripheral vision most people do not realize they have the disease at this point and often present for care when the damage to the eye nerve is advanced. With frequent evaluation of the eye pressure and health of the eye nerve – early changes can be identified and treatment can be started before marked damaged is done to the nerve.

How does the optic nerve get damaged by open-angle glaucoma?

The cause and process of damage to the eye nerve is complex but is most often attributed to an increase in pressure inside the eye. This is typically either caused by too little fluid that flows out of the front fluid chamber of the eye, or by an over production of fluid into the front eye chamber (anterior chamber).

This causes an increased pressure inside the eye which in turn causes an increased pressure on the eye nerve at the back of the eye. Just as nerves in the spine loses their normal function under increased pressure – so the eye nerve loses its sensitivity to see in the peripheral field.  That’s why controlling pressure inside the eye is important.

De Jongh Optometry - World Glaucoma week - GlaucomaFluid pathway is shown with arrows

Will I develop glaucoma if I have increased eye pressure?

Not necessarily. Not every person with increased eye pressure will develop glaucoma. Some people can tolerate higher levels of eye pressure better than others. Also, a certain level of eye pressure may be high for one person but normal for another.

Whether you develop glaucoma depends on the level of pressure your optic nerve can tolerate without being damaged. This level is different for each person. That’s why a frequent comprehensive eye exam is very important.

Can I develop glaucoma without an increase in my eye pressure?

Yes. Glaucoma can develop without increased eye pressure. This form of glaucoma is called low-tension or normal-tension glaucoma. It is also a type of open-angle glaucoma.

How do I know I’m at risk for open-angle glaucoma?

Anyone can develop glaucoma. Some people, listed below, are at higher risk than others:

  • People of African descent over age 40
  • Everyone over age 60
  • People with a family history of glaucoma
  • People with high blood pressure
  • People with diabetes

To protect the health of your eyes – make sure you have a comprehensive eye examination at least once every two years

How is glaucoma treated?

Glaucoma treatments include medication (eye drops), laser drainage surgery, conventional surgery, or a combination of any of these. While these treatments may save remaining vision, they do not improve sight already lost from glaucoma.

What is the latest advancements in the detection of glaucoma?

With Optical Coherence Tomography (OCT) assessment, the thickness of the optic nerve fibres can be monitored for thinning and can give a lead to early diagnosis of between 5 and 8 years before defects in the visual field develops.  At De Jongh Optometry we invest in cutting edge technology and can offer OCT assessment to our patients to secure early detection and referral.

De Jongh Optometry - Optical Coherence Tomography

What are the symptoms of glaucoma?

Initially there is no changes in vision and no pain. Gradual loss of sensitivity develop in one or both eyes. Without treatment, people with glaucoma will slowly lose their peripheral (side) vision. As glaucoma remains untreated, people may miss objects to the side and out of the corner of their eye. They seem to be looking through a tunnel. Over time and without treatment, straight-ahead (central) vision may decrease until no vision remains.

To watch a video animation of glaucoma click the link below:-


How is glaucoma detected?

Glaucoma is detected through a comprehensive eye exam that includes the following:

  • Visual acuity test. This eye chart test measures how well you see at various distances.
  • Tonometryis the measurement of pressure inside the eye by using an instrument called a tonometer. A tonometer measures pressure inside the eye to detect glaucoma
  • Visual field test. This test measures your peripheral (side vision). It helps your eye care professional tell if you have lost peripheral vision, a sign of glaucoma.
  • Dilated eye exam. In this exam, drops are placed in your eyes to widen, or dilate, the pupils. Your eye care professional uses a special magnifying lens to examine your retina and optic nerve for signs of damage and other eye problems.

Contact us to schedule your appointment and remember to like us on Facebook for up to date news and events.

Moreleta Park Branch on (012) 998 7592/3 

Lynnwood Branch (012) 807 6027