WHAT IS GLAUCOMA AND HOW CAN YOU PREVENT IT?

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Glaucoma affects roughly

728,000 CANADIANS

Educating yourself about glaucoma and understanding the many risks associated with it is an important step to help protect and preserve your eye health.

What is Glaucoma?

Glaucoma is a group of eye diseases that lead to the progressive degeneration of the optic nerve, causing a loss of nerve tissue and potential blindness. The cause of these diseases are not always known, however, they can result in optic nerve damage through elevated intraocular pressure (IOP) or a restriction in blood supply to the nerve, also known as poor perfusion.

Either way, the optic nerve progressively loses viability, resulting in visual field or peripheral vision loss. This vision loss will usually first appear in the peripheral vision, a warning sign that Glaucoma may be present or on the horizon. A routine eye exam can often determine if you are predisposed to Glaucoma, steps you can take to prevent and/or treat it.

While glaucoma can happen to anyone, here are some common risk factors that can contribute to the diagnosis:

  • Being over 60 years old

  • A family history of glaucoma

  • Medical conditions, such as diabetes, heart disease, high blood pressure, or sickle cell anemia

  • Corneas that are thin in the centre

  • Eye injuries

  • Being extremely nearsighted, farsighted, or taking corticosteroid medications, like eye drops, for a prolonged period

  • Having elevated eye pressure

Four types of glaucoma

Diagram of an eye anatomy with focus on the optic nerve.

Primary open-angle glaucoma

Primary open-angle glaucoma (POAG) is the most common type of glaucoma. It occurs when the eye’s drainage channel remains fully open. POAG includes both high-tension glaucoma—caused by elevated eye pressure from excess aqueous fluid or insufficient drainage—and normal-tension glaucoma, caused by reduced blood flow to the optic nerve rather than increased eye pressure.

Cross-section illustration of an eye showing optic nerve detail.

Normal-tension glaucoma

This type of glaucoma occurs when the drainage channel in the eye, located at the angle formed between the cornea and the iris, closes or becomes blocked.


The risk of the drainage channel closing increases with age in certain individuals. If the channel closes, permanent optic nerve damage can occur in only hours.

Cross-section illustration of an eye highlighting the optic nerve connection.

Secondary glaucoma

This type of glaucoma can occur as the result of an injury, eye surgery, infection, or tumour growth in or around the eye, causing pressure to rise. It has also been linked to a variety of medical conditions, medications, and eye abnormalities.

Illustration of an eye cross-section focusing on the optic nerve.

Angle-closure glaucoma

This type is caused when the drainage angle in the eye formed by the cornea and the iris closes or becomes blocked. As you age, the drainage angle between the cornea and the iris can shut, creating a buildup of eye pressure and fluid.

Diagnosing Glaucoma

A routine eye exam can help identify early signs or risk factors of Glaucoma. At FYidoctors, many of our optometrists have advanced diagnostic imaging tools for Glaucoma testing and diagnosis:

  • Ophthalmoscopy

  • Retinal Imaging

  • Tonometry

  • Perimetry

  • Gonioscopy

  • Optical Coherence Tomography (OCT)

Treating Glaucoma

Although there is no cure for glaucoma, treatment and prevention protocols do exist to prevent further damage and vision loss. Treatment typically is offered in one of two ways—medication or surgery.

Beta Blockers

The most common beta blocker used is timolol. These drugs reduce production of aqueous humor (fluid in the eye), which will lower pressure.

Alpha Agonists Production

Alpha agonists decrease aqueous humor productions and increase the outflow of liquid from the eye. Both activities lower IOP. An example of an alpha agonist is brimonidine.

Carbonic Anhydrase Inhibitors

Common CAIs are brinzolamide or dorzolamide. They are applied to the eye and will also decrease the production of aqueous humor.

Miotics

A common miotic is pilocarpine. This particular medication increases outflow of liquid and decreases IOP.

If medication is unsuccessful, doctors may recommend that a patient should consider having surgery. A routine eye exam is the best way to determine if you are predisposed to Glaucoma, steps you can take to prevent and/or treat it.

Source: Fighting Blindness Canada

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