Glaucoma is an eye disease that disrupts the proper functioning of the optic nerve. The optic nerve cells are damaged by excessive pressure from the liquid in the eyeball. It is one of the most common causes of blindness in Canada. Glaucoma is typically gradual and may not be noticed until it is advanced.
The vision loss caused by glaucoma cannot be reversed, so it's essential to have your eyes examined regularly to prevent it.
The causes
Other risk factors for glaucoma include aging (over 40), elevated intraocular pressure (IOP: pressure inside the eye), myopia, diabetes, high blood pressure and a history of eye injury.
The most significant difficulty with glaucoma is the absence of symptoms, as you can't feel the pressure in your eye. Only a few people experience headaches, red eyes or blurred vision. If a thorough eye examination by an optometrist is not carried out regularly, the first symptom to appear is permanent "holes" in the field of vision or "tunnel vision" in advanced stages. Untreated glaucoma often leads to blindness.
Diagnosis
The first thing your optometrist should check is the eye's internal pressure. A pulsed-air tonometer is used to measure it without direct contact with the eye. The optometrist can also examine the eye through the transparent pupil using an ophthalmoscope. This examination is essential, as normal-pressure glaucoma cannot be diagnosed based on eye pressure. Early damage caused by glaucoma can be detected by assessing visual fields.
Treatment and prevention
Various medications are available to relieve eye pressure and prevent damage. Most are administered in the form of eye drops. However, these drugs must be taken for the rest of the patient's life, and glaucoma patients often prefer surgery or laser treatment.
The most common procedure is laser trabeculoplasty. The procedure is performed in 15 minutes on an outpatient basis and is painless. The laser light causes no damage as it passes over the eye's surface, as its energy is focused on the trabecular meshwork, reducing its volume and clearing the openings. After this operation, people can often stop taking their glaucoma medication. Other surgical interventions are also possible should this maneuver fail.
If glaucoma is treated early, vision loss can be minimized or prevented. As glaucoma is often asymptomatic, it is essential to have a complete eye examination periodically, especially if the following risk factors are present:
- family history of glaucoma
- myopia
- previous eye injury
- high blood pressure
- diabetes
- prolonged exposure to prednisone, cortisone or other steroids.
If you are between 40 and 64 and have no risk factors for glaucoma, a complete eye examination should be performed every 2 years. After age 65, your eyes should be examined every year. However, if you are at risk, your eyes should be examined as often as your optometrist recommends.
