What is Glaucoma?

Causes of Glaucoma

The primary cause of glaucoma is an increase in intraocular pressure (IOP), which can damage the optic nerve. In most cases, elevated IOP is caused due to a buildup of fluid, known as aqueous humor, that flows throughout the eyes. Usually, a tissue near the intersection of the iris and cornea is where it drains. Another name for this tissue is the trabecular meshwork. The cornea allows light to enter the eye, which is why it is essential to vision.

When the eye makes too much fluid or the drainage system doesn’t work properly, the eye pressure can increase and lead to optic nerve damage. However, the exact mechanisms leading to elevated IOP and subsequent optic nerve damage may vary, depending on the type of glaucoma.

Open-angle glaucoma

This is the most common form of glaucoma but the exact cause of the disease is not clear as it is associated with a gradual increase in intraocular pressure. In this condition, the drainage angle of the eye remains open, but the trabecular meshwork becomes less efficient over time.

Angle-closure glaucoma

In this type of glaucoma, the iris bulges causing the drainage angle of the eyes to become blocked. This leads to a sudden increase in intraocular pressure, caused by the aging process, anatomical variations, or a combination of factors.

Normal-tension glaucoma

In this form, optic nerve damage occurs even with normal intraocular pressure. The exact cause is not well understood, but factors such as reduced blood flow to the optic nerve, genetics, and pressure sensitivity may contribute to the problem.

Glaucoma in children

Congenital glaucoma can occur in infants due to abnormalities in the eye’s drainage system. It usually develops either at birth or in the first few years of life.

Secondary glaucoma

This glaucoma is associated with other eye conditions or systemic diseases.
Some of the causes of this type include eye injuries, inflammation, certain medications, and conditions such as diabetes.

Key Facts of Glaucoma

Major Symptoms	Eye pain or pressure Headaches Rainbow-colored halos around lights Low vision Blurred vision Narrowed vision Blind spots Nausea and vomiting Red eyes
Necessary Health Tests	Tonometry Ophthalmoscopy Perimetry (Visual field test) Gonioscopy Pachymetry
Treatment	Medications Laser therapy Surgery

Symptoms of Glaucoma

At first, glaucoma doesn’t usually have any symptoms which is why half of the people who get affected by the disease don’t know that they have it. Since it shows no typical signs of glaucoma, it is often referred to as the “silent thief of sight.”

The vision loss is gradual and may go unnoticed until significant damage has occurred. However, some symptoms and signs of glaucoma may become apparent. Here are the potential symptoms:

Open-angle glaucoma:

• Gradual loss of peripheral vision
• Tunnel vision or narrow vision
• Difficulty adjusting to low light conditions

Angle-closure glaucoma

• Severe headaches
• Sudden and severe eye pain
• Blurred or hazy vision
• Halos around lights
• Redness in the eye
• Nausea and vomiting

Normal-tension glaucoma

Similar to open-angle glaucoma, it may cause a gradual loss of peripheral vision.
No specific symptoms are unique to normal-tension glaucoma.

Congenital glaucoma

• Dull or cloudy eye
• Blurred vision
• Increased blinking
• Nearsightedness that gets worse
• Headache

It is important to note that the symptoms mentioned here are not exclusive to glaucoma and can be associated with other eye conditions as well. You must go for regular eye examinations, especially for individuals who are at a higher risk of developing these problems.

Diagnosis of Glaucoma

As mentioned, glaucoma doesn’t show any symptoms. So, it is important to do regular eye exams to detect the problem. The diagnosis of glaucoma may include:

• Medical history: The eye care professional will ask about your medical history, including any family history of glaucoma.
• Tonometry: This test measures intraocular pressure (IOP), which is a key risk factor for glaucoma. It involves using an instrument to measure the pressure inside the eye.
• Ophthalmoscopy: The doctor will use a special magnifying lens to examine the optic nerve at the back of the eye. Changes in the appearance of the optic nerve head can indicate glaucoma.
• Perimetry (Visual Field Test): This test measures your peripheral (side) vision. Loss of peripheral vision is a common sign of glaucoma.
• Gonioscopy: This test examines the drainage angle of the eye to determine if it is open or closed. A special lens is used to visualize the drainage structures.
• Pachymetry: This measures the thickness of the cornea. Corneal thickness can influence intraocular pressure readings.

Treatment of Glaucoma

The treatment of glaucoma aims to lower intraocular pressure (IOP) to prevent or slow down the progression of optic nerve damage. Common treatment options include:

1. Medications

This is the most common form of treatment. They either increase the drainage of fluid from the eye or reduce the production of aqueous humor to lower intraocular pressure. They are either given in the form of eye drops or pills.

2. Laser therapy

Doctors use lasers to improve the drainage of fluid from the eye, reducing intraocular pressure. It is a simple procedure that won’t take a long time.

3. Surgery

Surgery is taken into account when medicines and laser treatment don’t work out. Several surgeries can help with the disease. The most common ones include:

• Trabeculectomy: It creates a new drainage channel to allow fluid to leave the eye, reducing intraocular pressure.
• Minimally invasive glaucoma surgery (MIGS): These are newer surgical techniques that aim to improve the drainage of fluid from the eye with less risk and a shorter recovery time compared to traditional surgery.
• Drainage devices: In some cases, a drainage device (shunt or tube) may be implanted to help regulate intraocular pressure.
• Combination therapies: A combination of medications, laser therapy, and surgery may be recommended to effectively manage intraocular pressure.

While these treatments can help manage glaucoma, they cannot reverse vision loss that has already occurred. Early detection and treatment are crucial to preventing further damage to the optic nerve and preserving vision.