Glaucoma is one of the leading causes of irreversible blindness worldwide, affecting millions of individuals. This condition is particularly concerning because it often progresses silently, sometimes without noticeable symptoms, until significant vision loss occurs. The importance of routine eye exams cannot be overstated, especially for those with a family history of glaucoma, as early detection is vital to managing the disease and preserving vision. Currently, it's estimated that approximately 780,000 people in Canada are living with glaucoma. 

What is Glaucoma?

Glaucoma is a group of eye conditions characterized by damage to the optic nerve, often associated with increased pressure inside the eye (intraocular pressure). The optic nerve is vital for vision, and its damage can lead to progressive, permanent vision loss. The exact cause of the optic nerve damage in most cases of glaucoma is not fully understood, making early detection and treatment crucial.

Different Types of Glaucoma:

The two main types of glaucoma are open-angle glaucoma and angle-closure glaucoma. Open-angle glaucoma, the most common form (about 90% of all cases), occurs when the eye's drainage canals become clogged over time, leading to increased eye pressure. Angle-closure glaucoma (about 10% of all cases), although less common, is a medical emergency and occurs when the iris is too close to the drainage canal, suddenly blocking fluid from exiting the eye and causing a rapid increase in pressure.

Signs and Symptoms of Glaucoma:

In its early stages, glaucoma may present no symptoms. As the condition progresses, signs of glaucoma may include: 

1. Headaches 

2. Blurred Vision

3. Gradual loss of peripheral (side) vision, 

4. Tunnel vision in advanced stages,

5. Halo or Rainbows Around Lights

6. Pain or Redness in The Eyes

7. Acute angle-closure glaucoma; symptoms can include severe eye pain, nausea, redness in the eye, and blurred vision.

The reality, though, is that most people diagnosed with glaucoma have no symptoms at all and are only diagnosed through a routine comprehensive eye health exam with an optometrist. Based on the findings, your optometrist may get a second opinion from a glaucoma specialist or ophthalmologist to confirm the diagnosis. 

How Optometrists Diagnose Glaucoma

During a comprehensive eye exam, optometrists can detect glaucoma before symptoms begin. They may be able to perform many of these tests during a routine eye exam. In contrast, other ones may need to be scheduled at a later date and may need to be repeated multiple times. Some of the tests performed include:

Tonometry: is a diagnostic procedure to measure the intraocular pressure (IOP), or pressure inside the eye. The test is painless and quick, using a tonometer to gently apply pressure to the eye's surface or to direct a puff of air toward the eye. There are several types of tonometry:

1. Applanation Tonometry: This method involves using a device that touches the cornea to measure the force required to flatten a small part of its surface. A fluorescein dye is often applied to the eye to help the instrument make the measurement. The Goldman applanation tonometer, which is mounted on a slit lamp, is considered the gold standard for this method.

2. Non-contact Tonometry (NCT): Also known as the "air-puff" test, this method uses a puff of air to flatten the cornea momentarily. It does not require physical contact with the eye or the use of dye or medications, making it quick and comfortable for most patients.

3. Tono-Pen: A portable, handheld device that is gently tapped on the cornea to measure intraocular pressure. It's useful in various settings and for patients who cannot undergo standard tonometry due to their condition or posture. 

Ophthalmoscopy: also known as fundoscopy, is a medical procedure used to examine the eye's interior, specifically the back part, including the retina, optic disc, choroid, and blood vessels. This examination is critical for diagnosing and monitoring various eye conditions, such as glaucoma, diabetic retinopathy, macular degeneration, and retinal detachment. Ophthalmoscopy can be performed using a direct or indirect approach:

1. Direct Ophthalmoscopy: Involves the use of a handheld device called a direct ophthalmoscope that emits a beam of light to illuminate the back of the eye. The examiner views the eye's interior through a small lens on the device, offering a highly magnified but limited view of the retina.

2. Indirect Ophthalmoscopy: Utilizes a head-mounted or handheld light source and a handheld lens to project a less magnified but wider view of the eye's interior. This method allows for the examination of the peripheral retina and is often used in more comprehensive retinal examinations.

Gonioscopy: is a diagnostic eye examination procedure used to visualize the anterior chamber angle of the eye, the anatomical area where the cornea meets the iris. This angle is critical for the eye's aqueous humour drainage, and its assessment is essential in diagnosing and managing glaucoma, particularly in differentiating between open-angle and angle-closure types.

The procedure involves using a gonioscope, a special contact lens equipped with mirrors or prisms that allow the optometrist or ophthalmologist to view the angle directly. The examination is typically performed under a slit lamp microscope in a clinical setting. By evaluating the structure and openness of the anterior chamber angle, gonioscopy provides valuable information on the potential for aqueous humour outflow obstruction, aiding in determining the glaucoma type and guiding appropriate treatment strategies.

Optic Nerve Head Photography: is a non-invasive medical imaging technique used to capture detailed images of the optic disc, the point where the optic nerve enters the retina in the eye. This method is crucial for diagnosing, monitoring, and managing conditions that affect the optic nerve, such as glaucoma, by documenting changes in the appearance of the optic disc and surrounding retinal nerve fiber layer over time.

Optic nerve head photography can be performed using different ophthalmic imaging devices, including a traditional retinal camera or more advanced systems like the Optomap ultra-wide retinal imaging device.

1. Retinal Camera: A retinal camera, or fundus camera, is a specialized low-power microscope with an attached camera designed to photograph the interior surface of the eye, including the retina, optic disc, macula, and posterior pole. It provides high-resolution images essential for monitoring subtle changes in the optic nerve head over time. 

2. Optomap Ultra-Widefield Retinal Imaging Device: The Optomap device offers an ultra-widefield view of the retina, capturing more than 80% of the retina in a single image compared to the 15-45% coverage typical with conventional imaging methods. This broader perspective is particularly useful for detecting peripheral retinal abnormalities that might go unnoticed with standard imaging. The Optomap's panoramic imaging capability allows for a comprehensive assessment of the optic nerve head within the context of the entire retinal landscape.

Visual Field Testing: also known as perimetry, is a diagnostic procedure used to measure the full horizontal and vertical range and sensitivity of an individual's visual field. This test assesses the extent of the area a person can see peripherally (side vision) while focusing their eyes on a central point. 

Visual field testing in the context of glaucoma is a critical diagnostic and monitoring tool used to assess the presence and progression of vision loss associated with this eye disease. Glaucoma primarily affects the peripheral vision initially, often without noticeable symptoms until significant damage has occurred. The test measures the range and sensitivity of an individual's peripheral vision, identifying areas where vision may have been compromised due to damage to the optic nerve caused by elevated intraocular pressure, a hallmark of glaucoma.

Through a series of light stimuli presented at various points in the visual field, the test determines areas where the patient may not see the lights, indicating a visual field loss. These deficits, known as scotomas, are documented and analyzed to provide a visual field map, highlighting any reductions in sensitivity or blind spots.

Regular visual field testing over time allows healthcare providers to track the progression of glaucoma, offering insights into the effectiveness of treatment and the need for adjustments. By detecting changes in the visual field early, interventions can be implemented more effectively to slow the progression of glaucoma and preserve the remaining vision.

Treatments for Glaucoma:

While there's no cure for glaucoma, treatments can help control the condition. Options include prescription eye drops to reduce eye pressure, laser treatments to improve drainage, and surgical procedures to create a new drainage path. Treatment depends on the type and severity of glaucoma.

Depending on the type of glaucoma you are diagnosed with, treatment may be initiated by your optometrist. This treatment usually involves using prescription eye drops to control the eye pressure. Sometimes, your optometrist will refer you to a glaucoma specialist who may perform laser treatments or other surgical treatments. 

The Importance of Follow-Up:

Once diagnosed with glaucoma or if there are concerns, it's crucial to follow up with your optometrist regularly. Monitoring the condition allows for adjustments in treatment to prevent further vision loss. Adhering to prescribed treatments and attending scheduled appointments are key components of managing glaucoma effectively.

Glaucoma is a progressive condition that gets worse over time. Our goal, however, is to slow the rate of progression to preserve your vision and visual function for as long as possible. 

Conclusion:

Glaucoma's silent progression underscores the necessity of regular eye exams, particularly for those at higher risk. Recognizing the early signs and symptoms can lead to timely intervention, offering the best chance to preserve vision. If you or someone you know is at risk for glaucoma, scheduling an eye exam could be a vision-saving decision. You can contact us at our Kingsway Mall or St. Albert clinic or book your eye exam online using our 24/7 online scheduling software. 

Disclaimer: The content provided in this blog post by Stonewire Optometry eye care clinic in Kingsway Mall is intended solely for informational purposes and does not replace professional medical advice, diagnosis, or treatment by a Licensed Optometrist. No doctor/patient relationship is established through the use of this blog. The information and resources presented are not meant to endorse or recommend any particular medical treatment. Readers must consult with their own healthcare provider regarding their health concerns. Stonewire Optometry and its optometrists do not assume any liability for the information contained herein nor for any errors or omissions. Use of the blog's content is at the user's own risk, and users are encouraged to make informed decisions about their health care based on consultations with qualified professionals.