Are you at risk of getting glaucoma?

The simple answer to this question is yes – anyone can develop glaucoma. However there are certain risk factors that you may have which increase your risk of developing this disease. It is important to know if you do have these risk factors so that you can be more closely monitored. Unfortunately for the most part glaucoma does not have any symptoms until it is often too late – so regular monitoring by an optometrist or eye specialist is the only way the disease can be diagnosed early and vision loss prevented. We estimate that nearly half of all people with glaucoma in New Zealand are still to be diagnosed.

There are many different types of glaucoma and each type of glaucoma has it’s own risk factors. In New Zealand the most common type of glaucoma is called primary open angle glaucoma (POAG), which is due to a high pressure in the eye. The two main risk factors for this condition are having a family history and older age. If you have a family member (particularly a parent or sibling) with glaucoma then you have a much higher risk and a check up at least every 2 years with an optometrist is highly recommended. Your optometrist may want to see you more regularly if you have any suspicious features for glaucoma or if your other affected family members have more severe glaucoma. In addition, as you get older (particularly over 60 years) glaucoma and many other eye diseases like macula degeneration become more common and so a yearly eye exam would is recommended.

POAG is also more common in certain ethnicities in New Zealand. These include Caucasians, Asians and Indians. It is much less common in Maori and Polynesians. This type of glaucoma affects males and females equally. Other possible factors that may increase your risk include being shortsighted, having high blood pressure, diabetes, and steroid medication.

The second type of glaucoma commonly seen in New Zealand is called normal tension glaucoma (NTG). This is another form of open angle glaucoma that develops despite the eye pressure being normal. We think that patients with this condition may have a very sensitive optic nerve and/or there may be an issue with blood supply to the optic nerve. Once again family history and getting older are the main risk factors for this condition. However, with this type of glaucoma other contributing factors may include low blood pressure, anaemia, sleep apnoea, cardiovascular disease and a previous episode of major blood loss (for example with surgery or trauma). This disease is also more common in females and in people who get migraines.

One other type of glaucoma that is commonly seen in New Zealand is called angle closure glaucoma (ACG). This is quite different to POAG and NTG and is due to the drainage part of the eye (called the anterior chamber angle) blocking up leading to a rapid rise in eye pressure. Patient’s who develop ACG usually get this disease because of the shape or size of the eye (smaller than average). Having a slightly smaller eye also makes these patients long-sighted – hence this is a risk factor for this type of glaucoma. Once again, the risk increases as you get older and family history may be a factor although less so than in POAG and NTG. ACG is also more common in Asians and in females.

In summary, it is important that if you do have risk factors for glaucoma you are closely monitoring to ensure that if you do develop the disease it is diagnosed early. If you do not have any risk factors you can still develop glaucoma so a regular eye check with an optometrist is still needed.