What is glaucoma?
More than 250,000 Canadians have chronic open-angle glaucoma, the most common form of the disease.
Glaucoma occurs due to damage to the optic nerve. While it is not known exactly how this occurs, there is an association between damage to the optic nerve and pressure within the eye due to build up of excess fluid within the eye. Over time the disease develops into a loss of peripheral (side) vision.
There are several types of glaucoma that can be broken down into primary and secondary glaucoma:
Primary Glaucoma: Open-angle glaucoma accounts for 90 per cent of all cases in Canada. Initially you can perform all normal daily activities like driving and reading. Sight loss is not obvious until it is too late and permanent. With primary open-angle glaucoma, the normal drainage outflow mechanism in the eye becomes blocked, increasing fluid pressure inside the eye. However, some people may have what is called normal tension glaucoma, a type of open angle glaucoma in which damage to the optic nerve may occur even though the pressure within the eye is not elevated.
Primary Glaucoma: Primary acute closed-angle glaucoma results from a buildup of fluid in the eye because the distance between the iris and the drainage system has been closed, stopping fluid from draining from the eye. This type of glaucoma occurs very suddenly and is an emergency. There is often severe pain associated with this condition. Severe sight loss can occur if treatment is not sought immediately.
Primary Glaucoma: Chronic angle closure glaucoma also involves a narrowing of space between the iris and the drainage system, but it occurs more gradually than in the acute form of the condition (and can take weeks or even years). There are no symptoms other than sight loss.
Secondary glaucoma can result from a variety of other conditions like an eye injury or inflammation, eye surgery complications, diabetes and the use of certain medications.
How does glaucoma affect your sight?
Glaucoma occurs due to damage to the optic nerve. While it is not known exactly how this occurs, there is an association between damage to the optic nerve and pressure within the eye due to build up of excess fluid within the eye.
Over time the disease develops into a loss of peripheral (side) vision. If glaucoma is untreated it could advance to later stages where central vision narrows to "tunnel" vision, or it may result in complete loss of vision.
If you have any of the following glaucoma symptoms, see your eye doctor immediately:
- Primary open-angle glaucoma and chronic angle closure glaucoma have no symptoms other than eventual sight loss. Your sight will appear normal and there is no pain. You may not be aware you have glaucoma for a long time, despite the fact that you are losing your slowly.
- Acute closed-angle glaucoma occurs with a sudden onset of symptoms such as severe eye pain, blurred vision, nausea, redness in the eye and haloes around lights.
Risk factors include:
- Elevated pressure in the eye – People with higher than average pressure in the eye have an elevated risk of developing glaucoma.
- Family history – People with a family history of glaucoma are at a much higher risk of developing open-angle glaucoma.
- Age – after age 40 and after age 60. It is fairly common to develop glaucoma over the age of 40, with the risk increasing significantly for people over the age of 60
- Ethnicity – People of African descent are at a higher risk of developing open-angle glaucoma. Angle closure glaucoma is more common in people of Asian and Inuit ethnicity.
- Myopia – People who are nearsighted have an increased risk of developing glaucoma.
Diagnosis and treatment
If you have any risk factors or are experiencing any of the common symptoms for glaucoma, see an eye doctor right away.
Primary open-angle glaucoma can be treated, with the goal being to lower the pressure within the eye. This can be achieved through eye drops, laser treatment (Selective Laser Trabeculoplasty – SLT), conventional surgery, or minimally invasive glaucoma surgery (MIGS).
The following contain useful information on glaucoma: