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What are the 4 Types of Glaucoma?

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A doctor holding wooden blocks that spell "glaucoma"

Glaucoma is an eye condition that causes gradual damage to the optic nerve by increasing pressure within the eye, impairing vision. The optic nerve is what sends information from the eye to the brain.

Besides underlying conditions such as diabetes and high blood pressure, age is also a risk factor for developing glaucoma. Monitoring health and vision changes and having regular eye exams are thus crucial in diagnosing and treating the early signs of glaucoma. 

The most common type of glaucoma is open-angle glaucoma which more than 250,000 Canadians have. Let’s look at the 4 types of primary glaucomas in more detail. 

1. Open-Angle Glaucoma

Open-angle glaucoma is so common that it accounts for 90% of all cases in Canada. Typically, there are no signs or symptoms, and vision loss is gradual. 

Initially, there is no concern when driving and reading as vision loss occurs slowly. At the point before or when symptoms become apparent, irreparable damage to your vision can occur. 

Cause of Open-Angle Glaucoma

When fluid in the eye doesn’t drain fast enough, pressure buildup pushes on the optic nerve at the back of the eye. Over time, fluid pressure damages the optic nerve, thus affecting vision. 

Open-angle glaucoma can lead to blindness if not diagnosed and treated early. Risk factors include people with high blood pressure and diabetes. 

2. Angle-Closure Glaucoma

Also called narrow-angle or acute glaucoma, this type of glaucoma is rare. This condition is a medical emergency where if you experience any of the following symptoms, you should seek immediate medical treatment: 

  • Headaches
  • Intense eye pain
  • Nausea
  • Blurred vision
  • Red eyes

Causes of Angle-Closure Glaucoma

Angle-closure glaucoma, caused by a blockage, prevents the aqueous humor fluid in the eye from draining. The buildup of fluid causes a sudden, painful increase in pressure.

Angle-closure glaucoma can cause blindness if not treated. Treatment includes laser, surgery, or medication to unblock the drainage canals, help fluid drain, and lower eye pressure. Even though the condition is present only in one eye, treatment usually includes both eyes.

A senior woman getting her eyes examined at the optometrist

3. Normal-Tension Glaucoma

Also called low-tension glaucoma, this condition occurs where there is damage to the optic nerve but without elevated pressure within the eye, like in open-angle glaucoma. Risk factors include:

  • Family history
  • Japanese descent
  • Heart problems such as irregular heartbeat
  • Low blood pressure

Causes of Normal-Tension Glaucoma

The cause of normal-tension glaucoma is unknown, but it’s believed that factors unrelated to eye pressure may play a role. These include extreme sensitivity of the optic nerve, a lack of blood flow, abnormalities in blood flow to the optic nerve, or structural weakness of optic nerve tissue. 

Often the first sign of normal-tension glaucoma is loss of peripheral or side vision. The condition progresses slowly, accompanied by narrow vision. Treatment includes surgery, laser treatment, and medications to lower eye pressure and help slow the progression and prevent vision loss. 

4. Congenital Glaucoma

Congenital glaucoma is present at birth and affects 1 in 10,000 infants. In this condition, children are born with a defect that prevents the eyes from draining fluid. 

Often diagnosed in the first few months after birth or within the first year. Noticeable signs include:

  • Cloudy eyes
  • Sensitivity to light
  •  Excessive tearing
  • Larger than normal eyes
  • Shutting the eyelids

Causes of Congenital Glaucoma

It’s known that if the cells and tissues in a baby’s eye don’t develop and grow as they should, they can have trouble with fluid drainage in the eye after birth. Risk factors include a family history of the condition. 

Early diagnosis and treatment can preserve a child’s vision. Treatment involves surgery and medication, including follow-up and regular eye exams for ongoing eye health. 

Diagnosing  Glaucoma

There is no sure way to prevent glaucoma, but an early diagnosis can lower your risk of damage and vision loss. There are several ways to diagnose glaucoma, 2 methods to measure ocular pressure include:

  • iCare Tonometer: This method measures eye pressure without eye drops, anesthesia, or air puff. It uses a very light probe that makes contact with your cornea.
  • Goldmann Applanation Tonometer: With numbing drops, this method uses a flat-tipped cone to measure the pressure. 

Early Treatment Preserves Vision

Even though there is no cure for glaucoma, slowing the progression can prevent blindness. If you think you may have glaucoma or are concerned that you are at risk for the disease, book an appointment with View Pointe Vision + Style to test your eyes.

Written by Dr. Janelle Driedger

Dr. Driedger was raised in Manitoba but educated in Tennessee. A southern belle at heart, she has a knack for treating her patients like family. Dr. Driedger is a certified “eye-nerd” and relishes the opportunity to collect anything eye related. She has an eye for style and will happily show you her collection of fashionable eyewear. In optometry school, Dr. Driedger was voted “most likely to have a pink office” and loves the fact that her classmates’ predictions came true when she opened View Pointe in 2019.
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