Even in developed countries like Australia, glaucoma causes untreatable blindness and visual disability.
Like a thief in the night, it sneaks up undetected to steal your sight, often doing irreparable damage before it can be diagnosed and treated. This makes early detection of glaucoma essential.
There is no cure for glaucoma but once diagnosed it is usually possible to slow or stop the progress of the disease.
What is glaucoma?
Glaucoma is a group of related diseases that cause damage to the optic nervewhere it passes through the wall of the eye. This damage is usually due to a build-up of pressure in the eye through malfunction of the drainage channels within the eye.
There are four main types – primary open-angle glaucoma, primary closed-angle glaucoma, secondary glaucoma and congenital glaucoma. All are dangerous and require immediate treatment.
What causes glaucoma and who gets it?
Primary open-angle glaucoma is usually age-related and is most common in developed countries, with an incidence of between one and two per cent in people over 40, rising to ten percent in people over 70. People of African descent are in greater danger than those of Caucasian descent.
This form of glaucoma is caused when the drainage channels of the eye become blocked slowly over many years and there is a build-up of pressure within the eye that damages the optic nerve. It can, however, also occur without a pressure-build-up, making it more difficult to diagnose.
Often there are no physical symptoms of chronic glaucoma other than a gradual loss of peripheral vision, making regular eye examinations very important for older people.In many instances patients are not aware of the vision loss and already have substantial tunnel vision by the time they seek medical attention.
Insight Optometrists recommends a check-up every two years for everyone over 40 and more frequent examination if there is a family history of glaucoma, previous eye injury or vision problems, or for people prone to migraines, those have diabetes, or those who have high or low blood pressure.
Primary closed-angle glaucoma can occur at any age when there is a sudden blockage of fluid to or from the eye. Primary closed-angle glaucoma causes irritation, sudden vision deterioration or nausea and often, in the early stages, by coloured lights and hazy vision. It can be very painful or can occur in a series of mild attacks. If any of these symptoms occur you should see your doctor or optometrist immediately.
Secondary glaucoma develops when other medical conditions block the supply of fluid within the eye. The range of glaucoma causes includes surgery, advanced cataracts, eye injuries or severe inflammation. It can also be a complication of diabetes.
Congenital glaucoma is more common in boys than girls and occurs when a birth abnormality blocks the drainage channels within the eye. Diagnosis can be difficult as the child can’t tell you there is a problem but it is nevertheless usually detected within the first three months of life. If you notice your child’s eye is cloudy or enlarged you should contact your doctor immediately.
Testing and treatment
Your optometrist will perform a range of tests to check for glaucoma. These include viewing the optic nerve using special instrumentation, pressure testing (known as tonometry) and a field test (where spots of light are shown on a screen).The latest technology is using an OCT (Ocular Coherent Tomograhy) which uses wavelength technology to measure the retinal nerve fibre layer and ganglion cell count.
No one test is definitive enough to rule out glaucoma but a battery of the above tests performed over a period of time will ensure that the first signs of the disease are detected as early as possible.
Treatment usually starts with eye drops to lower pressure within the eye but in more severe cases it may involve laser treatment or surgery. Because glaucoma is often painless, patients sometimes fail to continue using the recommended medications and this has become a major cause of blindness or extensive vision loss in glaucoma patients.
While there is no known way to prevent glaucoma, recent research has shown that regular exercise, a healthy diet and abstinence from smoking can substantially reduce your risk of developing glaucoma and many other diseases.
Because of the high incidence of this disease and the fact that often glaucoma causes no apparent symptoms before substantial damage is done to your vision, early detection and treatment remains the best way to prevent severe vision loss or blindness.
Insight Optometrists cannot stress strongly enough the need for regular eye health checks, particularly for older patients more likely to develop glaucoma.
If you would like more information or have any questions about this article, please contact Insight Optometrists at [email protected].