Glaucoma is a group of eye diseases that damage the optic nerve, which transmits visual information from the eye to the brain. This damage is often due to increased pressure in the eye, although glaucoma can also occur when eye pressure is normal. It’s a major cause of vision loss, especially in people over 60, but can develop at any age. Glaucoma is a leading cause of blindness worldwide, but early diagnosis and treatment can slow or prevent further vision loss.

Causes of Glaucoma

Glaucoma is primarily caused by a buildup of fluid in the front part of the eye, which leads to increased pressure. This fluid, called aqueous humor, usually flows through the eye, nourishing it and then draining out through a spongy tissue (trabecular meshwork) where the iris and cornea meet. In glaucoma, this drainage system malfunctions, causing fluid to accumulate, which increases eye pressure. This pressure puts stress on the optic nerve, and over time, nerve fibers die off, resulting in vision loss.

Key risk factors for glaucoma include:

• Family history of glaucoma
• Age (60 or older, or 40 and older for African Americans)
• Increased eye pressure
• Thin cornea
• Severe nearsightedness
• Eye injuries or surgery
• High blood pressure, cardiovascular disease, or diabetes
• Use of corticosteroid medications

Symptoms of Glaucoma

Glaucoma is often called the “silent thief of sight” because most people do not experience symptoms until the disease is advanced. In the early stages, there are typically no noticeable signs, but as the optic nerve becomes damaged, vision begins to fade. Symptoms in advanced stages include:

• Blind spots in peripheral vision
• Tunnel vision, where only central vision remains

For closed-angle glaucoma, the most severe form, symptoms can develop rapidly and include:

• Blurred vision
• Eye pain
• Light sensitivity
• Rainbow halos around lights
• Headaches
• Nausea and vomiting

This form of glaucoma is a medical emergency and requires immediate attention to prevent permanent vision loss.

Types of Glaucoma

There are three main types of glaucoma:

1. Open-angle glaucoma: The most common form, where fluid drains too slowly even though the drainage channels remain open. It causes a gradual rise in eye pressure, eventually damaging the optic nerve and leading to vision loss.
2. Closed-angle glaucoma: Also called narrow-angle glaucoma, this occurs when the angle between the cornea and iris narrows too much, suddenly blocking fluid drainage and causing a rapid rise in eye pressure. This is a medical emergency.
3. Normal-tension glaucoma: In about 30% of cases, eye pressure remains normal, but the optic nerve still sustains damage. It may be related to factors such as abnormal blood flow in the eye, autoimmune diseases, or conditions like migraines or Raynaud’s phenomenon.

Treatments for Glaucoma

While there is no cure for glaucoma, early treatment can help slow or stop further vision loss. Treatment depends on factors such as the type and severity of the disease and the patient’s age. Options include:

1. Medicated eye drops: These reduce eye pressure by either improving fluid drainage or reducing fluid production in the eye.
2. Laser surgery: This creates an opening for fluid to drain from the eye. For open-angle glaucoma, laser trabeculoplasty stimulates drainage channels, while for closed-angle glaucoma, laser peripheral iridotomy creates a small hole in the iris to improve fluid flow.
3. Conventional surgery: If medication and laser surgery are ineffective, traditional surgery may be required. Procedures like trabeculectomy create new drainage channels for fluid. Micro-invasive glaucoma surgery (MIGS) uses tiny stents or shunts to increase fluid drainage with minimal disruption.

Early detection and regular eye exams are crucial, as up to half of people with glaucoma are unaware they have the condition. Managing risk factors and receiving prompt treatment can help preserve vision.