What is Glaucoma?

Glaucoma is an eye condition, also called “a silent thief of sight that affects the optic nerve (a bundle of about one million individual nerve fibers) of the eye and leads to blindness and vision loss if left untreated. The optic nerve transfers visual information from the eye to the brain. Glaucoma is associated with increased intraocular pressure (IOP) within the eye, but it can also occur with normal or even lower-than-normal eye pressure.

What are the types of Glaucoma?

There are various types of glaucoma, but two main categories are Angle-Closure Glaucoma and Open-Angle Glaucoma. Let’s explore some common types of glaucoma:

Open-Angle Glaucoma : Primary open-angle glaucoma is the most popular form of glaucoma. It happens due to the increased IOP inside the eyes that involves the overproduction of fluid within the eye and reduced outflow of fluid from the eye.

The symptoms of this type of glaucoma appear after many years because it is very slow in progress.

Angle-Closure Glaucoma : This type of glaucoma is associated with the sudden and gradual closure of the drainage angle in the eye. The drainage angle is the area where the cornea and iris meet, and it is responsible for allowing the fluid (aqueous humor) in the eye to drain properly. When this angle becomes blocked, the fluid cannot flow out of the eye efficiently, leading to a rapid increase in intraocular pressure.

Normal-Tension Glaucoma : This type of glaucoma is also called low-tension glaucoma, where optic nerve damage and vision loss occur despite intraocular pressure (IOP) consistently measuring within the normal range. In typical glaucoma cases, elevated intraocular pressure is a primary risk factor for optic nerve damage, but in normal-tension glaucoma, the optic nerve is still affected even when the pressure is considered normal.

Secondary Glaucoma : Secondary glaucoma is when elevated intraocular pressure and optic nerve damage result from another underlying eye condition or systemic health issue. Secondary glaucoma can be associated with various factors, including eye trauma, certain medications (such as steroids), inflammation (uveitis), tumors, and vascular disorders.

Congenital Glaucoma : congenital glaucoma is a rare type of glaucoma that occurs in infants and young children. It is present at birth or develops shortly afterward. Usually, congenital glaucoma is an abnormal development of the eye’s drainage system (trabecular meshwork). The impaired drainage leads to increased intraocular pressure, potentially causing damage to the optic nerve and vision loss.

Pigmentary Glaucoma : Pigmentary glaucoma occurs when pigment granules from the iris (colored part of the eye) disperse and accumulate in the eye’s drainage system, affecting the flow of aqueous humor. This dispersion of pigment is often associated with the rubbing or movement of the iris against the lens. Over time, the pigment can clog the drainage channels, leading to increased intraocular pressure.

What are the Symptoms of Glaucoma?

Glaucoma commonly develops slowly and does not cause noticeable symptoms in early stage. As the disease progresses, people may experience symptoms associated with increased IOP and optic nerve damage.

Some Common Glaucoma Symptoms are:

• Tunnel vision
• Gradual loss of side or peripheral vision
• Blurry vision
• Colored rings or halos around the lights
• Headache and eye pain
• Nausea and vomiting
• Red eye
• Patchy Blind spots

How is glaucoma diagnosed?

Your eye doctor will check your medical history, conduct a complete eye examination, and perform some tests that include:

• Tonometry- measure intraocular pressure
• Dilated eye exam – test optic nerve damage
• Visual field test- check vision loss areas
• Pachymetry- measure the thickness of the cornea
• Gonioscopy- inspect the angle of drainage

Glaucoma Medications

Generally, glaucoma is controlled with eye drops. The use of eye drops every day, lowers the pressure of the eye.

Some do this by lowering the aqueous fluid amount that is produced by the eyes and others lower the pressure by facilitating improved fluid management vis the drainage angle.

The medication for glaucoma helps you keep your vision but some eye drops cause side effects like dry mouth, itching sensation, altered energy level, eyelash growth, changes in eye color, and red eyes.

Glaucoma Treatments

Laser Therapy

• Selective Laser Trabeculoplasty (SLT): This laser procedure is used to improve drainage by targeting the trabecular meshwork. SLT is often considered for open-angle glaucoma.
• Laser Peripheral Iridotomy (LPI): LPI is used for angle-closure glaucoma to create a small hole in the iris, allowing fluid to flow more freely and reducing pressure.

Glaucoma Surgery

• Trabeculectomy: This surgical procedure creates a new drainage channel to lower intraocular pressure. It involves creating a small flap in the sclera (white part of the eye) to allow fluid to drain.
• Minimally Invasive Glaucoma Surgery (MIGS): MIGS procedures are less invasive than traditional surgeries and are aimed at improving drainage. 
• Glaucoma Drainage Implants: Glaucoma drainage implants are small prosthetic devices that are placed to help drain excess fluid and reduce intraocular pressure.

It’s important to note that early detection of glaucoma disease through regular eye exams is crucial for managing and treating glaucoma effectively, as the condition often progresses without noticeable symptoms in its early stages. Treatment may involve medications, laser therapy, or surgery, depending on the type and severity of glaucoma.

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Written and Verified by:

DR. DEEKSHA PANT

MBBS, MS, DNB & FAEH (CORNEA)

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