Understanding Glaucoma
Glaucoma often comes without symptoms — but can lead to permanent blindness.
Learn how early detection and your support can protect and preserve sight.
What is Glaucoma?
Glaucoma is one of the leading causes of irreversible blindness, affecting over 250,000 Canadians. Often called the “silent thief of sight,” it damages the optic nerve — usually without any warning signs. This damage is commonly caused by increased pressure inside the eye due to fluid buildup.
If left untreated, glaucoma can gradually steal a person’s peripheral (side) vision and eventually lead to complete vision loss. There are several forms of glaucoma, which are typically categorized as primary or secondary types.
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.
Primary Glaucoma: Open-Angle
Open-angle glaucoma accounts for 90% 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
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
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
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.