Glaucoma, a common eye condition, affects millions of people worldwide. While many may have heard of glaucoma, fewer are familiar with its two main types: open-angle and closed-angle glaucoma. Understanding the differences between these two types is essential for recognizing symptoms and seeking timely treatment. Here, Dr. Neal Guymon, known on YouTube as Dr. EyeGuy, explains the key distinctions between open-angle and closed-angle glaucoma, along with a breakdown of symptoms, and treatment approaches.*

Open-Angle Glaucoma: The Silent Threat to Sight

Open-angle glaucoma (OAG) is the most common form of the disease and progresses slowly over time. In OAG, the “angle” of the eye, formed by the junction of the iris and cornea, remains open, but the trabecular meshwork (the eye’s drainage system) becomes at least partially blocked or clogged, causing fluid in the eye to drain too slowly and build up, leading to a slow increase in eye pressure.

This increase in internal eye pressure, also known as intraocular pressure (IOP), damages the optic nerve, interfering with communication between your eye and your brain. 

This type of glaucoma can result in long-term or permanent vision loss if left untreated. Unfortunately, since OAG is often asymptomatic in its early stages, many people don’t realize they have it.

Closed-Angle Glaucoma: A Medical Emergency

Closed-angle, or angle-closure, glaucoma (ACG) occurs when the drainage angle of the eye is completely blocked, causing a rapid rise in eye pressure. Unlike OAG, ACG produces sudden onset of painful symptoms, making it a medical emergency requiring immediate treatment.

Symptoms of ACG can include: 

• Severe pain (eye and/or head), 
• Nausea,  
• Blurred vision, 
• Red eyes, and 
• Light sensitivity.

The rapid changes in IOP cause rapid damage to the optic nerve, which can result in permanent vision loss and blindness without immediate emergency medical attention.

Treatment and Risk Management

Both OAG and ACG are related to increased eye pressure, though their progression and symptoms differ. Treatment focuses on lowering eye pressure through:

• Medicated eye drops, 
• Oral medications, 
• Laser therapy, and/or 
• Surgical procedures, ranging from minimally-invasive (MIGS) to significantly invasive.

Those with narrow angles can speak with their doctors about undergoing preemptive procedures to reduce their risk of acute attacks.

By understanding the distinctions between open- and closed-angle glaucoma, and recognizing early warning signs, you can seek appropriate treatments in time to protect your vision.

*Guymon, N. [Dr. EyeGuy]. (2023, August 26). Open Vs. Closed Angle Glaucoma (Painful Glaucoma!) [Video file]. Retrieved from https://www.youtube.com/watch?v=-Qeb68ENq9k 

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