Glaucoma:

Introduction

Glaucoma is a group of eye conditions that damage the optic nerve, which is crucial for good vision. This damage is often caused by abnormally high pressure in the eye. Glaucoma is one of the leading causes of blindness for people over the age of 60. However, it can occur at any age but is more common in older adults.

Understanding Glaucoma

Glaucoma is known as the "silent thief of sight" because it often has no symptoms until noticeable vision loss occurs. The most common types of glaucoma include open-angle glaucoma and angle-closure glaucoma.

Open-Angle Glaucoma

Open-angle glaucoma is the most common form. It occurs when the eye’s drainage canals become clogged over time. This results in increased eye pressure and damage to the optic nerve. It is called "open-angle" because the angle where the iris meets the cornea is wide and open.

Angle-Closure Glaucoma

Angle-closure glaucoma, also known as closed-angle glaucoma, occurs when the drainage angle formed by the cornea and the iris closes or becomes blocked. The result is a sudden increase in eye pressure, leading to pain and rapid vision loss.

Causes and Risk Factors

Glaucoma is primarily caused by increased pressure in the eye (intraocular pressure). This pressure can damage the optic nerve, which transmits images to the brain. If the damage progresses, glaucoma can cause permanent vision loss or even blindness within a few years.

Increased Eye Pressure

Increased eye pressure occurs when the fluid (aqueous humor) that flows throughout the eye cannot drain properly. Normally, this fluid exits the eye through a drainage system called the trabecular meshwork at the angle where the iris and cornea meet. When the fluid is overproduced or the drainage system does not work correctly, the fluid can't flow out at its normal rate, causing intraocular pressure to increase.

Risk Factors

Several factors can increase the risk of developing glaucoma, including:

• Age: People over 60 are at increased risk.
• Ethnicity: African Americans and Hispanics are more likely to develop glaucoma than Caucasians.
• Family History: Having a family history of glaucoma increases your risk.
• Medical Conditions: Conditions like diabetes, high blood pressure, and heart disease can increase risk.
• Physical Eye Injuries: Severe eye injuries can cause secondary open-angle glaucoma.
• Long-term Use of Corticosteroid Medications: Particularly eye drops.

Symptoms

Symptoms of glaucoma vary depending on the type and stage of the condition. In general, the symptoms can include:

Open-Angle Glaucoma Symptoms

• Patchy blind spots in your side (peripheral) or central vision, frequently in both eyes.
• Tunnel vision in the advanced stages.

Acute Angle-Closure Glaucoma Symptoms

• Severe headache
• Eye pain
• Nausea and vomiting
• Blurred vision
• Halos around lights
• Eye redness

Diagnosis

Early diagnosis of glaucoma is crucial in preventing serious vision loss. Eye exams can include several tests to diagnose glaucoma:

Tonometer Test

This test measures the intraocular pressure using a device called a tonometer. A tonometer measures the pressure by blowing a small puff of air at the eye or by applying a tiny amount of pressure with a device.

Ophthalmoscopy

In this test, the doctor uses a special device to look through the pupil and examine the shape and color of the optic nerve.

Perimetry

Also known as a visual field test, perimetry maps the visual field to check for any visual field loss.

Gonioscopy

This procedure uses a special lens to look at the angle where the iris meets the cornea to see if it is open or closed.

Pachymetry

A pachymeter measures the thickness of the cornea. This is important because corneal thickness can affect intraocular pressure readings.

Treatment

While there is no cure for glaucoma, early diagnosis and treatment can control the condition and prevent further vision loss. Treatments for glaucoma aim to reduce intraocular pressure and can include medications, laser treatment, and surgery.

Medications

Medications are usually the first line of treatment for glaucoma and can come in the form of eye drops or pills. These medications work by either reducing the production of fluid in the eye or improving the drainage of fluid from the eye. Common medications include:

• Prostaglandins: Increase the outflow of the fluid in the eye, thereby reducing eye pressure.
• Beta Blockers: Reduce the production of fluid in the eye.
• Alpha Agonists: Reduce the production of fluid and increase drainage.
• Carbonic Anhydrase Inhibitors: Reduce fluid production in the eye.
• Rho Kinase Inhibitors: Reduce eye pressure by decreasing fluid production and improving fluid drainage.

Laser Treatment

Laser therapy can be used to treat open-angle glaucoma and angle-closure glaucoma. In open-angle glaucoma, laser trabeculoplasty helps to open clogged channels in the trabecular meshwork. In angle-closure glaucoma, laser iridotomy creates a small hole in the iris to improve fluid flow.

Surgery

When medications and laser treatments do not adequately control intraocular pressure, surgery might be necessary. Surgical options include:

• Trabeculectomy: A surgical procedure where a small piece of the trabecular meshwork is removed to create a new drainage pathway.
• Drainage Tubes: Small tubes are inserted into the eye to help drain fluid and reduce eye pressure.
• Minimally Invasive Glaucoma Surgery (MIGS): A group of surgical procedures that use