Glaucoma

Overview

Glaucoma is an eye disease that damages the optic nerve causing vision loss and sometimes blindness. The National Coalition for Vision Health says at least 300000 Canadians have glaucoma and half of them don't even know it. Although it often occurs in older people it can develop at any age.

Symptoms

Glaucoma is called the silent thief of sight because it typically has no symptoms until partial vision loss has occurred. Loss of vision due to glaucoma is irreversible.

Causes

In the front of the eye clear fluid flows in and out of a space called the anterior chamber. When the fluid passes out too slowly and builds up pressure can increase sometimes rising to the point where it damages the optic nerve. This form of the disease the most common is called open angle glaucoma because the fluid leaves the anterior chamber at the open angle where the cornea and the iris meet. Some people have glaucoma and optic nerve damage even without the pressure within the eye rising -- a type called low-tension or normal-tension glaucoma. It isn't known exactly why this occurs in people but risk factors include:

  • age
  • family history
  • nearsightedness
  • poor health (such as early heart attack or stroke)

Treatment

Regular routine eye exams including special tests can improve the odds of early detection. Once detected the disease can be controlled -- and remaining vision preserved with improved medicine and surgery techniques.

During an exam for glaucoma doctors will also look at the optic nerve measure the intraocular pressure and evaluate peripheral vision -- often affected first in glaucoma.

To lower the pressure inside the eye drops are commonly prescribed. Some of the newer eye drop medicines only need to be taken once or twice a day. Drops work either by causing the eye to make less fluid or helping the fluid drain.

There is also surgery in which a laser is aimed at the lens of the eye making several evenly spaced burns stretching the drainage holes inside the eye and allowing the fluid to escape.

Prevention

Since glaucoma risk rises with age The Glaucoma Research Foundation says eyes should be tested at about age 35 and 40 then every two to four years after age 40 and every one to two years after age 60. Those at high risk due to family history of glaucoma should get exams every one to two years after age 35.