What is Glaucoma?

Glaucoma is often called the “sneak thief of sight” as most people with glaucoma do not notice symptoms until they begin to have significant vision loss. As optic nerve fibres are damaged by glaucoma, small blind spots may begin to develop, usually in the peripheral or side vision.

There are two types of Glaucoma:

  1. Open Angle Glaucoma: Most common variety – potentially blinding
  2. Closed Angle Glaucoma: Less common potentially blinding

In most cases this is caused by high intra-ocular pressure (IOP), a result of blockage of the circulation of aqueous or drainage of the aqueous. In other cases the damage may be caused by low blood supply to the optic nerve, weakness of the structure of the optic nerve or another health problem in optic nerve. You can have glaucoma with normal eye pressure too.

Personal history:

If you are 40 years or over, have a family history of glaucoma, you are short sighted or have diabetes, then you are at risk of glaucoma.

A prior serious eye injury, the use of steroids regularly over a long period of time, or hypertension, puts you at a higher risk of glaucoma developing.

If you are in a high-risk category you should begin having your eyes examined well before age 35 years.


Common symptoms of acute angle closure are related to sudden increases in IOP, and may include:

  • blurred vision
  • halos around lights
  • severe eye pain
  • headache
  • nausea and vomiting


The common type of glaucoma is not symptomatic until late. Therefore it is important to have your eye pressure checked by an optometrists or eye specialist. Glaucoma is most commonly treated with eye drops. If treatments such as drops fail, surgery may be required. In angle-closure glaucoma, iridotomy laser surgery may need to be done where a drainage hole is created in the iris to relieve the increased pressure inside the eye. This can be performed using a laser; therefore, an incision in the eye is not needed. Patients may need to have an iridotomy after an acute episode of angle-closure glaucoma or to prevent an attack of angle-closure glaucoma in the other eye.

The new iStent can be implanted during cataract surgery to help control the eye pressure.

Other types of surgery that are performed to help glaucoma include trabeculoplasty and filtering. All of these procedures try to ease drainage of aqueous.

For more information: