Glaucoma is a leading cause of preventable vision loss and blindness in older individuals in Canada and the second leading cause of blindness in the World, even more than macular degeneration.

Glaucoma is a disease that causes damage to the optic nerve due to an increase in pressure inside the eye. When detected in the early stages, glaucoma can often be controlled, preventing severe vision loss and blindness. However, symptoms of noticeable vision loss often only occur once the disease has progressed. This is why glaucoma is called “the sneak thief of sight”. Unfortunately, once vision is lost from the disease, it can’t be restored.

Prevention of glaucoma is possible with early detection and treatment. Since symptoms are often absent, regular eye exams which include a glaucoma screening are essential.


The buildup of pressure in the eye causes damage to the optic nerve which is responsible for transmitting visual information from the eye to the brain. This causes a slow loss of peripheral vision over time resulting in tunnel vision. If left untreated, central vision will also be affected, eventually causing blindness. Unfortunately, any vision that is lost from optic nerve damage cannot be restored.

Treatment for glaucoma can include medicated eye drops, pills, laser procedures and minor surgical procedures depending on the type and stage of glaucoma.

What are the Symptoms?

Typically, glaucoma sets in without any symptoms. At the early onset of the most common type of glaucoma “open angle” glaucoma, vision remains normal and there is no pain or discomfort.

An acute type of glaucoma, called angle-closure glaucoma, can present sudden symptoms such as foggy, blurred vision, halos around lights, eye pain, headache and even nausea. This is a medical emergency and should be assessed immediately as the intraocular pressure can become extremely high and cause permanent damage within hours.


Detecting Glaucoma

During a comprehensive eye exam your optometrist will examine the optic nerve for signs of glaucoma and will also measure the intraocular pressure (IOP) with an instrument called a tonometer.

Visual Field Test

A visual field test is designed to detect any blind spots in your peripheral vision. You will be asked to place your head in front of a machine while looking ahead and indicate when you see a light in your side vision.

Retina Testing

Your doctor may also measure the thickness of the cornea in a test called pachymetry and use imaging techniques such as optical coherence tomography (OCT) to create an image of your optic nerve to look for glaucoma damage.

Treating Glaucoma

Treatments include medication or surgery that can regulate the pressure and slow down the progression of the disease to prevent further vision loss. The type of treatment depends on the type and the cause of glaucoma.

Medicated eye drops to lower IOP are often the first treatment for controlling glaucoma. These drops may have some uncomfortable side effects, but compliance with the treatment plan is essential for preserving vision and halting the progression of the disease.

If medicated eye drops are not successful in reducing the eye pressure, surgical procedures are used to improving the drainage of fluid from the eye. Your doctor may decide that a combination of surgery and medication will be the most effective in many cases.


It cannot be stressed enough that glaucoma needs to be detected and treated early before significant vision loss occurs. Any vision that is lost cannot be restored. The best prevention is awareness and taking responsibility by having your eyes examined on a regular basis.