Glaucoma

What is Glaucoma?

Glaucoma is a group of eye diseases that gradually steals sight without warning and often without symptoms, so regular eye exams are recommended. Vision loss is caused by damage to the optic nerve. This nerve acts like an electric cable with over a million wires and is responsible for carrying the images we see to the brain.

Different types of Glaucoma

The two main types of glaucoma are open angle glaucoma, or primary open angle glaucoma (POAG), and angle closure glaucoma.

Primary Open Angle Glaucoma

This is the most common form of glaucoma. It happens when the eye’s drainage canals become clogged over time. The inner eye pressure (also called intraocular pressure or IOP) rises because the correct amount of fluid can’t drain out of the eye. With open angle glaucoma, the entrances to the drainage canals are clear and should be working correctly. The clogging problem occurs inside the drainage canals, like the clogging that can occur inside the pipe below the drain in a sink.

Most people have no symptoms and no early warning signs. If open angle glaucoma is not diagnosed and treated, it can cause a gradual loss of vision. This type of glaucoma develops slowly and sometimes without noticeable sight loss for many years. It usually responds well to medication, especially if caught early and treated.

Open angle glaucoma can be controlled but not cured. The most common treatments are medication usually eye drops, laser surgery or surgery.

Angle Closure Glaucoma

This type of glaucoma is also known as acute glaucoma or narrow angle glaucoma. It is less common and is very different from open angle glaucoma in that the eye pressure usually goes up very fast. This happens when the drainage canals get blocked or covered over, like the clog in a sink when something is covering the drain.

With angle closure glaucoma, the iris and cornea are not as wide and open as it should be. The outer edge of the iris bunches up over the drainage canals, when the pupil enlarges too much or too quickly. This can happen when entering a dark room. A simple test can be used to see if your angle is normal and wide or abnormal and narrow.

Treatment of angle closure glaucoma usually involves surgery to remove a small portion of the outer edge of the iris. This helps unblock the drainage canals so that the extra fluid can drain. Usually surgery is successful and long lasting. However, you should still receive regular check-ups.

Symptoms of angle closure glaucoma may include headaches, eye pain, nausea, rainbows around lights at night, and very blurred vision.

More Information

• Guidelines following glaucoma surgery – English or French
• Guidelines following trabeculectomy – English or French
• Laser Iridotomy – English or French
• Laser diode procedure post-op instructions – English or French
• Glaucoma Research Society of Canada