What is Glaucoma?
Glaucoma is a complex disease that is usually caused by a gradual increase in intraocular pressure (IOP) on the optic nerve. It is rare in people under 40 and the risk of developing glaucoma increases slightly with each year of age.
Glaucoma is the leading cause of blindness in people over the age of 60.
It is the gradual nature of the disease that makes glaucoma so insidious. As eye pressure builds up progressively, parts of the optic nerve become damaged irreversibly. Over time, if untreated, the progression of glaucoma results in vision loss.
The optic nerve is the bundle of nerve fibres that run like a communication cable from the back of your eyes to your brain.
Although glaucoma cannot be prevented, if it is diagnosed and treated early, glaucoma can usually be controlled.
What are the types of Glaucoma?
There are several types of glaucoma. The two most common types are Primary Open-Angle Glaucoma (POAG) and Primary Angle-Closure Glaucoma (PACG).
Primary Open-Angle Glaucoma is the most common form of glaucoma in Australia. It is characterised by high intraocular pressure (IOP) in the eye, which damages the optic nerve and leads to loss of peripheral vision.
Primary Angle-Closure Glaucoma is more common in long-sighted eyes, older people, women and in Asian populations. It is caused by an inherited narrowness of the drainage angle of the eye.
What are the Glaucoma risk factors?
Age. The risk of developing glaucoma increases slightly with each year of age, particularly for people over the age of 60.
Family history. As many as 40 to 60 percent of all patients with glaucoma have a family history of glaucoma. First degree relatives (parents, siblings and children) are at greater risk – they have an almost one in four chance of developing glaucoma in their own lifetime, and that risk doubles if the relative has advanced glaucoma.
Ethnicity. Asia accounts for almost 60 percent of the world’s total glaucoma cases. People of Asian descent are at higher risk of angle-closure glaucoma. People of Japanese descent are more likely to develop low-tension glaucoma.
When should you see your eye doctor?
Glaucoma is sometimes called the ‘sneak thief of sight’ because it slowly damages the eyes before there is any vision loss.
Glaucoma Australia estimates that over 300,000 people in Australia have glaucoma, however, only 50 percent know they are living with the disease. There are no warning signs for most types of glaucoma and self-diagnosis is not possible.
All Australians 50 years or older should visit their eye doctor (optometrist) at least every two years for a comprehensive eye exam, which would include a glaucoma check.
Those who have a family history of glaucoma or are of Asian or African descent, are encouraged to get their eyes checked at least every two years from the age of 40.
What sort of eye examination will you have?
There is no one single diagnostic eye examination for glaucoma. Your optometrist will perform a variety of tests, using a variety of devices to look for glaucoma symptoms and will then analyse the clinical findings. The glaucoma tests are completely painless.
What are the treatment options?
Glaucoma does not go away and there is no cure. Glaucoma treatment is aimed at reducing pressure in the eye. Regular use of prescription eye drops is the most common treatment and often the first treatment. Sometimes cases may require systemic medications, laser treatment, or eye surgery.
How can you live with Glaucoma?
As long as a glaucoma diagnosis is provided early and managed well, most patients with glaucoma continue to enjoy a full life. Lifestyle changes would need to be made and adherence to the recommended course of treatment has to become part of a normal routine.
To learn more about glaucoma, speak with an eye doctor (optometrist).
Your local Eyecare Plus optometrist will provide you with all the eye health information you need about glaucoma.
What about marijuana treatment for Glaucoma?
In the early 1970s, hopes were, well, ‘high’ when studies showed that smoking marijuana lowers intraocular pressure (IOP). Gradually, however, the clinical consensus on the use of marijuana for the treatment of glaucoma has changed. Today, medical opinion is nearly unanimous in asserting that the beneficial effects of marijuana have been overstated. How did marijuana lose its status as a miracle drug for glaucoma?
The short answer is that further studies revealed serious limitations to its actual use in glaucoma. First, there are doubts about its effectiveness in lowering chronic eye pressure because the human body develops a tolerance that limits its usefulness.
Second, the lowering of the pressure in your eye is notoriously brief (three to four hours), and would require constant dosing – some reports estimate that it would require eight to 10 marijuana cigarettes a day to maintain 24 hour IOP control.
The side effects are even more substantial when you consider that, because glaucoma is a chronic condition, a patient would be required to inhale or ingest substantial doses of cannabis every day, possibly for the remainder of adult life.
Leaving aside the concerns about the serious cardio-pulmonary and psychoactive side effects, this treatment would be expensive – much more expensive than established glaucoma treatments currently in use.
In the final analysis, current glaucoma medications more consistently lower IOP with fewer side effects and with a longer duration of action. Eyecare professionals and the Australian Department of Health maintain that marijuana should not be used in the management of glaucoma. The best way to treat glaucoma is with the prescribed therapies combined with long-term monitoring of the disease.