Glaucoma

Glaucoma is a group of diseases that can damage the eye’s optic nerve and may result in vision loss and blindness. The type of vision loss is the main characteristic of the disease: vision is lost from the surround or periphery before affecting "straight ahead" vision.  Multiple factors are often important in causing glaucoma, but it is most commonly related to hereditary and increasing age. Symptoms are most often entirely absent until the condition has progressed to an advanced stage.  Hence the need to be checked.

You may be more likely to develop glaucoma if you:
 
  • have someone else in your family with glaucoma
  • are over 40 years
  • are either short- or long-sighted
  • are known to have high pressure in your eye
  • have experienced injury to your eye in the past
  • have migraine or circulation problems.
 
The following tests are used to diagnose and monitor glaucoma:

  • Visual field testing (mapping of the surround vision).
  • Tonometry – measures eye pressure. It is often the first screening test for glaucoma. The eyes are numbed with eye drops and then examined. 
  • Dilated eye exam - this is done with an ophthalmoscope (a medical instrument that allows the doctor to look through the pupil to the back of the eye). The retina and optic nerve are then examined for any sign of the typical glaucoma damage. 
 
The only method at present for slowing the progression of glaucoma is  to reduce the pressure in the eye. Although glaucoma cannot be cured, early treatment can prevent further worsening of the condition and vision loss. Regular eye examinations are required life-long.

The eye is like a soccer ball in that it has no shape unless it is pumped up. It is not pumped up with air but with a special clear fluid called aqueous which is continuously made within the eye and continuously drains out. The pressure of the eye can be manipulated by reducing the production of aqueous or by increasing the drainage of aqueous.

Eye drops are the most common early treatment.  Surgery may be required, especially if medications are not taking adequate effect or the drops are causing troubling ocular irritation.

Laser iridotomy is a very useful procedure for reducing the risk of angle closure glaucoma - the glaucoma that most often affects long-sighted people.

Glaucoma - intraocular lens surgery. Long-sighted people tend to have shorter eyeballs. The lens inside the eye enlarges with life and can get to be as fat as 5 mm. This increase in lens size which occurs over a lifetime eventually puts the natural drainage pathways at the front of the eye under pressure because the eyeball remains the same size. In serious cases glaucoma - intraocular lens surgery is recommended. This procedure, which is done under local anaesthetic, sees the enlarged natural lens replaced with a thin silicone or acrylic lens, greatly increasing the drainage space at the front of the eye.

Trabeculectomy surgery is a method of reducing the pressure in the eye by making a small hole in the side of the eye and allowing the eye fluid to drain out beneath the skin of the eye where it is resorbed into the blood stream. This method achieves the lowest intraocular pressure of any of the methods for patients at highest risk of ongoing vision loss. It is also a very good method of reducing reliance on eye drop medication.

Laser trabeculoplasty is a useful laser technique that can reduce the pressure well in some people, avoiding the need for drops or surgery.

This page was last updated at 9:47AM on February 10, 2021.