Learning about Glaucoma

You may have glaucoma and not know it

Glaucoma often has no symptoms. Glaucoma is an eye disease that involves damage to the optic nerve. This nerve sends visual signals to the brain, where they are processed into what you “see”.

Glaucoma develops slowly over time. Many people will go years before noticing any symptoms. Often they don't know they have glaucoma until they lose some of their eyesight. Loss of vision from glaucoma is not reversible.

Protect yourself with regular eye exams. Eye doctors can detect and treat glaucoma before you experience any symptoms. If you have glaucoma, get proper treatment and regular eye exams.

What Is Glaucoma?

Glaucoma is an eye disease that involves damage to the optic nerve. This nerve sends visual signals to the brain, where they are processed into what you “see”. No one knows exactly what causes glaucoma but pressure buildup in the eye is proven to be a major risk factor.

diagram of an eye with major parts labeled

When pressure in the eye gets too high, the optic nerve can get damaged. This damage causes some signals from the eye not to reach the brain. The result is that you can’t “see” everything your eye sees. This leads to a reduced visual field, and if not managed, may even lead to blindness.


What Are the Symptoms of Glaucoma?

a visual depiction of the effects of tunnel vision

Many people don’t know they have glaucoma until they lose some of their eyesight. However, eye doctors can detect and treat glaucoma before most patients experience any symptoms.

Glaucoma develops slowly over time, which is why many patients will go years before noticing any symptoms. Patients with glaucoma may experience a gradual narrowing of their peripheral vision.

This loss of eyesight is also called “tunnel vision”. Unfortunately, loss of vision due to optic nerve damage can’t be reversed.


Why is Intra-Ocular Pressure (IOP) So Important?

Your eye is filled with fluids that help maintain a certain pressure in the eye. This is called intra-ocular pressure (IOP). Doctors can easily measure IOP and use it as an important gauge in the diagnosis and treatment of glaucoma. Normal IOP is about 12 to 22 mm Hg (millimeters of mercury).

One of the most common and important tests for measuring IOP is tonometry. Tonometry is a procedure in which your doctor uses a tonometer to measure IOP. This test is important because high IOP is a major risk factor for glaucoma. However, high IOP doesn’t necessarily mean you will have glaucoma, nor does normal IOP mean you don’t have glaucoma.

Controlling IOP is the major goal of glaucoma therapy. When IOP is controlled, the optic nerve is less at risk of being damaged, so vision may be preserved.


What Causes High IOP?

The front of the eye is filled with a specific fluid called the aqueous humor. This is produced by the eye to bathe and nourish its different parts. The aqueous humor normally flows out of the eye through various paths and chambers. When these paths get clogged, aqueous humor gets trapped in the eye. This causes a pressure buildup and leads to high IOP. High IOP is a major risk factor for glaucoma, but it can be treated.

a visual depiction of how intraocular pressure (IOP) can build up in the eye


Information on this page provided by Alcon Canada Inc.

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Quick Facts

  • By 2020 glaucoma will affect 80 million people globally
  • Glaucoma is the second leading cause of blindness in older North Americans
  • More than 400,000 Canadians have glaucoma today
  • World-wide, 6.6 million people are blind from this disease
  • With an increasingly long-lived seniors’ population and an aging baby boom generation, many more people will have glaucoma in the future
  • There is no cure yet for glaucoma, but researchers are working hard to find new treatments and discover a cure

Risk Factors

Glaucoma strikes people of every race, gender, and nationality. Anyone can develop glaucoma, but some people are at greater risk. If you meet one or more of the following criteria, you have an increased risk:

  • Over the age of 40
  • Family history of glaucoma
  • Abnormally high eye pressure
  • African, Asian, or Hispanic ancestry
  • Diabetic
  • Nearsighted
  • Regular, long-term use of steroids/cortisone
  • Previous eye injury.

If you are at risk, get regular eye check-ups.There is no cure for glaucoma but there are medications that can help slow its progress, so early detection and treatment of glaucoma is important.