Glaucoma is a progressive and chronic eye disease that damages the optic nerve, leading to vision loss and ultimately, blindness if left untreated. In most cases, the disease develops slowly and painlessly, making it difficult to detect until it has progressed significantly. While there is no known cure for glaucoma, early detection and treatment can help slow the progression of the disease and prevent or minimize vision loss. Glaucoma is caused by increased pressure in the eye, which can damage the optic nerve over time. The pressure buildup is often the result of a buildup of aqueous humor, the clear fluid that flows in and out of the eye. When the fluid cannot flow out of the eye properly, it accumulates and causes an increase in eye pressure, which can lead to damage to the optic nerve.

According to the World Health Organization, approximately 80 million people worldwide have glaucoma, with an estimated 6 million people suffering from blindness due to the disease. In Canada, it is estimated that over 700,000 people have glaucoma, with an additional amount of people who are believed to have the disease but have not yet been diagnosed. This number is expected to increase significantly in the coming years as the Canadian population ages and the prevalence of the disease rises.

Types of Glaucoma

There are different types of glaucoma, with the three main types being open-angle glaucoma, angle-closure glaucoma, and normal-tension glaucoma; and each type has its own unique characteristics and treatment options.

Open-Angle Glaucoma

Open-angle glaucoma is the most common type of glaucoma, accounting for over 70% of cases. It occurs when the trabecular meshwork, the drainage system in the eye that regulates the flow of aqueous humor, becomes blocked over time, leading to a gradual increase in intraocular pressure (IOP). This increase in IOP can damage the optic nerve, resulting in vision loss. Open-angle glaucoma is often called the “silent thief of sight” because it typically does not cause any noticeable symptoms until significant damage has already occurred. This is why regular eye exams are crucial in detecting the disease early and preventing vision loss. Some common risk factors for open-angle glaucoma include age, family history, ethnicity, and certain medical conditions such as diabetes and hypertension. Treatment for open-angle glaucoma usually involves reducing IOP through using eye drops, laser surgery, or traditional surgery. Eye drops work by reducing the amount of fluid produced in the eye or by increasing the flow of fluid out of the eye. Laser surgery can be used to increase the outflow of aqueous humor or to create a small hole in the iris to improve fluid drainage. In severe cases, traditional surgery may be necessary to create a new drainage channel for the fluid to leave the eye.

Angle-Closure Glaucoma

Angle-closure glaucoma is less common than open-angle glaucoma but is considered a medical emergency as it can cause sudden and severe loss of vision. It occurs when the iris bulges forward and blocks the drainage angle, preventing aqueous humor from flowing out of the eye. This blockage can lead to a rapid increase in IOP, causing damage to the optic nerve. Angle-closure glaucoma can cause symptoms such as severe eye pain, nausea, vomiting, and blurred vision. It is more common in individuals who are farsighted or have a shallow anterior chamber depth in their eyes. Other risk factors include age, ethnicity, and family history. The treatment for angle-closure glaucoma is usually an emergency laser procedure called iridotomy. During this procedure, a small hole is made in the iris to allow the aqueous humor to flow freely, relieving the pressure in the eye. In some cases, medications may also be prescribed to lower IOP and reduce inflammation.

Normal-Tension Glaucoma

Normal-tension glaucoma, also known as low-tension glaucoma, is a less common form of glaucoma in which the optic nerve is damaged despite normal intraocular pressure. This type of glaucoma is not fully understood and may be related to poor blood flow to the optic nerve or other factors. Normal-tension glaucoma is often diagnosed through a comprehensive eye exam that includes visual field testing, optic nerve imaging, and measurement of IOP. Treatment for normal-tension glaucoma typically involves lowering IOP through the use of eye drops, laser surgery, or traditional surgery. In addition, other underlying medical conditions such as high blood pressure and sleep apnea may need to be addressed to improve blood flow to the optic nerve.

Risk Factors

While anyone can develop glaucoma, certain risk factors increase the likelihood of developing the disease. These include age, ethnicity, family history, and certain medical conditions.

Age, for example, is one of the most significant risk factors for developing glaucoma, with individuals over the age of 60 being at the highest risk. When it comes to ethnicity, African Americans and individuals who are Hispanic and over the age of 40 are also at a higher risk of developing glaucoma compared to other racial and ethnic groups. Family history is another significant risk factor for glaucoma. Individuals with a first-degree relative, such as a parent or sibling, who has glaucoma are up to four times more likely to develop the disease themselves. This is because glaucoma is often inherited and can run in families. Medical conditions that can also contribute to glaucoma include diabetes, hypertension, and cardiovascular disease. These conditions can affect blood flow to the optic nerve, leading to damage and increasing the risk of glaucoma.

Regular eye exams are crucial in detecting glaucoma early and preventing vision loss. It’s recommended that individuals over the age of 40, or those with a family history of glaucoma, have a comprehensive eye exam every one to two years. During an eye exam, an ophthalmologist will measure intraocular pressure, examine the optic nerve, and perform visual field testing to check for signs of glaucoma.