Eye health: Glaucoma
March 10–16 is World Glaucoma Week. According to the Canadian National Institute for the Blind (CNIB), glaucoma is the second most common cause of vision loss in seniors in Canada, after age-related macular degeneration.
Glaucoma occurs when there is a buildup of pressure in the eye, which then causes damage to the optic nerve. If glaucoma is not treated, it can cause blindness within a few years. Glaucoma can strike at any age.
Types of glaucoma
There are four types of glaucoma:
- Open-angle glaucoma is the most common type in North America. The CNIB says that more than a quarter of a million Canadians have open-angle glaucoma. Your eye has fluid, called intraocular fluid, in the front part of the eye. When everything is working as it should, the fluid flows through the pupil and is absorbed back into the body. With open-angle glaucoma, this fluid does not flow through as quickly as it should, so the fluid builds up, causing an increase in intraocular pressure (IOP) in the eye. The pressure continues to build over time.
- Angle-closure glaucoma is not as common as open-angle glaucoma, but it is an emergency when it does happen. Acute angle-closure glaucoma occurs when the fluid flow is suddenly blocked, causing an immediate backup in the eye and a quick rise in pressure.
- Congenital glaucoma is a type that affects babies, who are born with it.
- Secondary glaucoma is caused by something that caused the glaucoma to develop, such as a side effect of a medication, a disease or trauma to the eye.
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Risks for glaucoma
Anyone can develop glaucoma, but as with many diseases, some people have higher risks than others. These include people who
- Are older
- Have a family history of glaucoma
- Are nearsighted
- Have diabetes or high blood pressure (hypertension)
- Take steroid medications (such as prednisone)
- Are of African, Asian, Hispanic or Inuit descent
If you have had acute-angle closure glaucoma in one eye, you have a higher risk of it developing in the other eye.
While you can't change some of these risk factors, such as your family history, age or ethnicity, some risk factors are "modifiable," as they say in medicine. People who smoke should try to stop, particularly if they have any of the other risk factors that can't be changed. If you have diabetes or high blood pressure, you can try to reduce your risk of developing glaucoma by taking good care of yourself and managing your disease as well as you can.
The symptoms of glaucoma depend on the type you have. Most people learn they have open-angle glaucoma only when it is diagnosed during an eye exam. Symptoms, such as a decrease in peripheral vision (along the sides of your line of vision), show up only after a lot of the damage has been done. However, if you show any signs of acute-angle glaucoma, see a doctor immediately, even if it has to be a hospital emergency department — this is a medical emergency. The symptoms include the following:
- Pain in the eye
- Narrowing and/or blurred vision
- Redness in the eye
- Haloes or shadows around lights
It is important to have regular eye exams, particularly as you get older or if you have any risk factors. One test, tonometry, is very quick. Using a quick puff of air directed at your eye, the optometrist or ophthalmologist can measure your intraocular pressure. You might also have drops put into your eyes so the doctor can look inside.
Another common exam is called the perimetry exam. For this, you look straight ahead, and the doctor checks to see what you can see with your peripheral vision.
Treatment for glaucoma is essential to prevent the disease from progressing. While it can't be cured, it can most often be managed and slowed down. Eye drops are the most common way to manage glaucoma, but other methods are evolving, such as laser or conventional surgery. The type of treatment a person receives is based on many factors, and you should discuss all your options with your doctor.