Glaucoma

Disclaimer

Dr. Marcelo T. Nicolela, MD. Associate Professor Faculty of Medicine Department of Ophthalmology & Visual Sciences Dalhousie University Halifax, NS Canada

• I was just diagnosed with glaucoma. What is glaucoma?
• Dear doctor, can you explain what are the different types of glaucoma?
• My doctor told me I have ocular hypertension. What is the difference between glaucoma and ocular hypertension?
• I was told that glaucoma leads to blindness. I am curious to learn how?

Question:
I was just diagnosed with glaucoma. What is glaucoma?

Answer:
Dear glaucoma patient, glaucoma is a progressive disease that affects the optic nerve (the nerve that transmits images to the brain) and results in loss of peripheral vision at first and can, at its later stages, lead to permanent blindness. In fact, glaucoma is one of the leading causes of blindness in Canada and in other parts of the world.

  
Question:
Dear doctor, can you explain what are the different types of glaucoma?

Answer:
There are two main forms of glaucoma, each one with several subgroups: Open angle glaucoma and Closed angle glaucoma.

Open angle glaucoma is the most common form of glaucoma in the Western world. If affects approximately 1 to 2% of the population over the age of 40 years. “Open” refers to the fact that your physician has a clear view of the drainage angle of your eye when it is examined. The disease is caused by an increase of the intraocular pressure in the eye due to a restriction to the flow of aqueous humour through the trabecular meshwork.
Open angle glaucoma also includes normal tension glaucoma (where the pressure in the eye is normal but the eye has the same optic nerve disease).

  
Question:
My doctor told me I have ocular hypertension. What is the difference between glaucoma and ocular hypertension?

Answer:
The condition in which the eyes have elevated intra-ocular pressure but there is no sign of glaucoma (no sign of loss of vision or optic nerve damage) is called “ocular hypertension”. Many patients with high pressure do not develop glaucoma.

  
Question:
I was told that glaucoma leads to blindness. I am curious to learn how?

Answer:
Glaucoma is the name given to a group of conditions that affect the optic nerve. The optic nerve is the nerve that transmits images to the brain. Damages to the optic nerve translate into patchy loss of vision at first and, in later stages, to blindness.

In most cases, the damage to the optic nerve is caused from an elevated pressure in the eye. The eye needs a certain level of pressure to keep its shape. The pressure is assured by a constant flow of fluids (aqueous humour) entering and leaving the eye, producing the required pressure (also call intra-ocular pressure). The loss of vision in glaucoma is permanent. Reducing the intra-ocular pressure helps prevent further deterioration in the optic nerve.