Glaucoma is the name given to a surprisingly common group of eye diseases in which the optic nerve at the back of the eye is destroyed resulting in loss of peripheral and if untreated, central vision. In most people this damage is related to an increase in intraocular pressure although in other patients poor blood supply to the optic nerve fibres, a weakness in the structure of the nerve, and/or a problem in the health of the nerve fibres themselves may cause the damage.
Over 300,000 Australians have glaucoma. It is as common as diabetes. While it is more common as people age, it can occur at any age. As our population becomes older, the proportion of glaucoma patients is increasing although a large number of patient with the condition remain undiagnosed.
The commonest forms of glaucoma are chronic open angle and acute and chronic angle closure forms with a number of other types also existing. Often the condition remains asymptomatic until eyesight is lost at a later stage due to a gradual, relentless, irreversible and imperceptible loss of peripheral visual field. Early detection and treatment can allow the process to be slowed down and arrested although what vision has been lost cannot be recovered.
Regular eye examinations are the best way to detect glaucoma early. Although anyone can get glaucoma, some people have a higher risk, those with a family history of glaucoma, diabetes, migraine, short sightedness (myopia), previous eye injury, high blood pressure, and past or present use of cortisone drugs (steroids). People in these groups should have their first eye check no later than the age of 35. For most people, it is recommended to have an eye check for glaucoma by the age of 40.
The assessment will include checking visual acuity, visual fields (usually with automated perimetry), central corneal thickness, optic nerve appearance using bi-microscopy, and ancillary diagnostic investigations such as OCT and HRT. Optic disc damage with or without elevated intra ocular pressure warrants further assessment to determine if treatment is necessary.
Although there is no cure for glaucoma it can usually be controlled and further loss of sight either prevented or at least slowed down. Treatments include:
- Eye drops – these are the most common form of treatment and must be used regularly. In some cases pills are prescribed. The drops can be varied to best suit the patient and the type of glaucoma.
- Laser (Selective Laser Trabeculoplasty) – this is performed when eye drops do not adequately lower the eye pressure so as to stop deterioration in the field of vision or can no longer be used. In many cases eye drops will need to be continued after laser. Laser does not require a hospital stay. The two techniques currently used are Selective Laser Trabeculoplasty (SLT) and Argon Laser Trabeculoplasty (ALT). SLT has largely replaced ALT and is discussed in more detail elsewhere on this site.
- Surgery (Trabeculectomy) – this is performed usually after eye drops and laser have failed to control the eye pressure. A new channel for the fluid to leave the eye is created. Treatment can save remaining vision but it does not improve eyesight.
For further information regarding glaucoma please contact Waverley Eye Clinic or visit Glaucoma Australia at http://www.glaucoma.org.au/