The front part of the eye is filled with a clear fluid, called intraocular fluid or aqueous humour. It is produced by the ciliary body and passes out of the eye through the eyes drainage system. The production, flow and drainage of this fluid is continuous, maintaining a steady pressure in the eye, called intraocular pressure.

What is Glaucoma?

Glaucoma is a disease of the optic nerve, the part of the eye that carries the signals from the eye to the brain. The optic nerve is made up of nerve fibres. Glaucoma occurs when the pressure in the eye (intra ocular pressure) builds up, as a result of a blockage in the eyes drainage system. This results in damage to the optic nerve fibres. 

Most patients with glaucoma have no early symptoms or pain, however, as damage occurs to the nerve fibres, patients tend to notice a reduction in their peripheral vision. The nerve damage is irreversible and can result in blindness if the entire nerve is destroyed. 


Types of Glaucoma

  • Open angle Glaucoma

This is the most common type of glaucoma and is also known as ‘Primary’ or ‘Chronic Open Angle’ Glaucoma. It occurs when the drainage system appears to be open but is not functioning properly, gradually increasing the pressure inside the eye. The damage progresses slowly and peripheral vision is gradually affected.

  • Closed Angle Glaucoma

This type is less common and is also known as ‘acute’ or ‘narrow angle glaucoma’. It causes a sudden increase in pressure inside the eye. Patients experience symptoms such as headaches, eye pain, nausea and halos around lights.

  • Normal tension Glaucoma

This is also known as low-tension glaucoma and is characterised by damage to the optic nerve with associated vision loss despite a normal eye pressure (intra-ocular pressure).

  • Congenital Glaucoma

This type of glaucoma occurs in babies and presents within the first 12 months of life. It is can be inherited and is caused by incorrect development of the eyes drainage system before birth.

  • Secondary Glaucoma

This type of Glaucoma occurs as a result of other disorders of the eye such as cataracts, inflammation of the eye or trauma.

Who is at risk of Glaucoma?

Some of the risk factors for developing glaucoma include:

  • Age
  • Elevated eye pressure
  • Other eye diseases
  • High Glasses Prescriptions
  • Past trauma or surgeries
  • Family history of glaucoma
  • Systemic conditions eg diabetes

Diagnosing Glaucoma

Regular eye examinations are important to monitor glaucoma/eye pressures.

Eye Pressure, or Intraocular pressure is measured in millimetres of mercury (mmHg). Normal eye pressures range from 10-21mmHg but tends to be greater than 21mmHg in patients with Glaucoma. Therefore, pressures need to be monitored regularly in the clinic.

Other tests that may be performed during your consultation include -

  • Measurement of the central central corneal thickness (CCT).
  • Inspection of the drainage angle of your eye (gonioscopy).
  • Visual field testing to assess peripheral vision
  • OCT (Optical Coherence Topography) scan and photos to assess the optic nerve and monitor any damage.

The tests are often performed on the initial visit in order to determine the extent of any damage or as a baseline evaluation of the optic nerve. They are then repeated on a regular basis in order to monitor any changes.

The Ophthalmologist at Western Sydney Eye Doctors will discuss the treatment options with you during your consultation.