Glaucoma - What You Should Know

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 Eye

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.

Who Gets Glaucoma?

Glaucoma strikes people of every race, gender, and nationality. Anyone can develop glaucoma, but some people such as those of African or Chinese descent are at greater risk than others. Studies have proven that anyone who meets one or more of the following criteria is at increased risk:

Over the age of 40
Family history of glaucoma
Abnormally high IOP
African, Chinese, Scandinavian, Celtic or Russian ancestry
Diabetic
Nearsighted
Regular, long-term use of steroids/cortisone
Previous eye injury

It is important that anyone with any of these risk factors get regular eye checkups. Early detection and treatment of glaucoma can slow the progression of the disease.

What Are the Symptoms of Glaucoma?

Sample 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.

Example of IOP build up

Eye Q Test

Eye Q Test – See how much you know about glaucoma — click here to take the test (Download PDF)