Glaucoma is a group of eye conditions that can damage the optic nerve, which is critical 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 sixty. Understanding glaucoma, its causes, detection methods, and treatment options is important for protecting your vision.

At Maine Eye Center, our eye doctors have the experience and training to help control glaucoma and prevent further vision loss.

What is Glaucoma?

Glaucoma is characterized by progressive damage to the optic nerve, which connects the eye to the brain. The optic nerve becomes damaged when the fluid pressure inside the eye, called intraocular pressure or IOP, rises too high. 

High IOP compresses and damages the fibers of the optic nerve. Over time, glaucoma can cause permanent vision loss and blindness if it is not treated.

What Causes Glaucoma?

In a healthy eye, a clear fluid called aqueous humor flows in and out of the anterior chamber to nourish the eye. The aqueous humor leaves the eye through a drainage system called the trabecular meshwork.

When the trabecular meshwork becomes clogged or blocked, fluid cannot flow out of the eye as easily. As more fluid builds up, the pressure inside the eye rises. 

This increased intraocular pressure causes damage to the optic nerve. Since heightened eye pressure is the most common cause of glaucoma, most treatment methods for glaucoma aim to lower eye pressure to help prevent further damage to the optic nerve.

What Are the Different Types of Glaucoma?

There are many different types of glaucoma. While all types of glaucoma cause damage to the optic nerve through increased eye pressure, they differ in the mechanism that leads to the rise in eye pressure.

Primary open-angle glaucoma is the most common type of glaucoma. This type of glaucoma typically occurs when there is a blockage in the drainage system within the eye, known as the trabecular meshwork. 

Angle-closure glaucoma is another type of glaucoma that occurs when the iris is too close to the drainage angle. The angle is the part of the eye that the fluid must flow through before reaching the trabecular meshwork.

When this angle becomes closed off, eye pressure can rise suddenly, potentially causing permanent vision loss rapidly. It is also possible to have glaucoma with average eye pressure levels.

This is called normal-tension glaucoma. Another type of glaucoma, called secondary glaucoma, occurs as a result of injury, inflammation, tumor, or in advanced cases of cataracts or diabetes.

Determining which type of glaucoma you have will help your eye doctor develop a treatment plan to help lower eye pressure.

How is Glaucoma Detected?

Glaucoma is called “the silent thief of sight” because early on, there are often no symptoms. As the eye condition progresses, some people experience tunnel vision or even total blindness.

Since glaucoma causes permanent vision loss, early detection is the best way to prevent damage and blindness. During a comprehensive eye exam, your eye doctor at Maine Eye Center in Portland, Maine, will test your intraocular pressure and examine the optic nerve. 

Other tests like imaging scans or visual field testing may be used to help diagnose glaucoma. These tests allow detection of glaucoma long before you experience vision loss. 

Regular eye exams are essential for protecting your sight from glaucoma.

Who Is At Risk For Glaucoma?

Anyone can develop glaucoma, but certain demographics have higher risks, including:

  • Age over sixty years old
  • Family history of glaucoma
  • African-American, Asian, or Hispanic ethnicity
  • Farsightedness or nearsightedness
  • Past eye injury or surgery
  • Use of corticosteroid medications
  • Health conditions including diabetes, migraines, poor blood circulation

It’s important to talk to your eye doctor about your glaucoma risk factors to determine an appropriate screening schedule. Catching glaucoma early is vital to preventing vision loss.

How Is Glaucoma Treated?

Although vision loss from glaucoma cannot be reversed, treatment can slow or halt further damage. Glaucoma treatment focuses on lowering intraocular eye pressure to a target level. 

This prevents ongoing injury to the optic nerve. There are a variety of glaucoma treatment options available. 

Your eye doctor at Maine Eye Center will determine the appropriate treatment plan based on your type of glaucoma, its severity, and your risk of progression and vision loss.


Eye drops, oral medications, and sustained-release implants can help reduce intraocular pressure. These glaucoma medications either decrease fluid production or improve drainage in the eye. 

This is typically the first line of treatment that eye doctors use to lower eye pressure levels. Consistent use is essential to success.

Laser Surgery

Laser surgery can help improve drainage to lower intraocular pressure. Types include selective laser trabeculoplasty (SLT), laser peripheral iridotomy, and cyclophotocoagulation.

These are outpatient procedures with minor risks. Additional laser surgery may be needed over time. 


Micro-invasive glaucoma surgeries (MIGS) include goniotomy procedures performed through tiny incisions. Goniotomy refers to opening up the drainage angle in the eye to improve the outflow of fluid. 

Two common goniotomy procedures are iStent and Hydrus stents. MIGS procedures help improve aqueous outflow and lower intraocular pressure by opening the eye’s natural drainage system. 

Glaucoma Surgery

Conventional incisional glaucoma surgeries are more invasive than MIGS procedures but are necessary in some cases. During traditional glaucoma surgery, your glaucoma surgeon will create a new drainage channel for the aqueous fluid to leave the eye. 

The new channel helps to lower the pressure. Traditional glaucoma surgery is often reserved for advanced cases not controlled by other methods.

Glaucoma causes permanent damage to the optic nerve, resulting in vision loss if left untreated. Medications, laser procedures, MIGS implants, and glaucoma surgery can effectively reduce pressure inside the eye to slow the progression of glaucoma. 

With early detection and treatment, it is possible to protect your vision from glaucoma. Regular eye exams and following your eye doctor’s treatment recommendations are key to successfully managing glaucoma.

Are you experiencing vision changes or symptoms associated with glaucoma? Schedule an appointment at Maine Eye Center in Portland, ME, today!