Narrow-Angle Glaucoma: Causes, Symptoms, and Treatment Options

Narrow-angle glaucoma (also called angle-closure glaucoma) is a serious eye condition where the drainage angle between the iris and the cornea becomes too narrow, leading to increased intraocular pressure (IOP). This rise in pressure can damage the optic nerve and, if untreated, may result in permanent vision loss.

This chart illustrates the average costs of glaucoma treatments in the U.S., including laser procedures, medications, and surgeries. Costs vary based on treatment type and severity of the condition.

Unlike open-angle glaucoma, which progresses slowly, narrow-angle glaucoma can develop suddenly and is considered a medical emergency. The condition is more common in people over 50, those with farsightedness (hyperopia), and individuals of Asian descent.

Causes and Risk Factors

The main cause of narrow-angle glaucoma is anatomical—some individuals are born with a naturally narrow drainage angle. However, certain factors can increase the risk of developing the condition:

• Aging – The lens thickens with age, pushing the iris forward and narrowing the angle.
  • Case Example: Sarah, a 62-year-old woman from California, noticed that her vision became blurry in dim light. Over time, her peripheral vision decreased, prompting her to visit an eye specialist. Tests confirmed age-related lens thickening leading to a narrow angle.
• Genetics – Family history plays a significant role in glaucoma risk.
  • Case Example: John, a 45-year-old man from Texas, had no vision problems but learned during a routine eye check-up that he had a high risk of angle-closure glaucoma. His mother had been diagnosed with the condition at age 60, highlighting the hereditary nature of the disease.
• Farsightedness (Hyperopia) – A shorter eye shape can contribute to a narrow angle.
  • Case Example: Maria, a 50-year-old teacher, had worn reading glasses for years. She began experiencing eye strain and occasional headaches. A comprehensive eye exam revealed that her hyperopia had contributed to a narrowing of her drainage angle.
• Medications – Some drugs, like antihistamines and decongestants, can trigger an acute attack by dilating the pupil.
  • Case Example: Tom, a 55-year-old man, took over-the-counter cold medicine and noticed a sudden onset of eye pain and halos around lights. He was rushed to the emergency room, where he was diagnosed with an acute angle-closure attack triggered by the medication.
• Dilating Eye Drops – Used in eye exams, these can sometimes cause angle closure.
  • Case Example: Linda, a 58-year-old patient, went for a routine eye exam that included pupil dilation. Shortly after, she developed severe eye pain and pressure, requiring immediate laser treatment to relieve the pressure.
• Low-Light Conditions – Pupillary dilation in dim environments may worsen the condition.
  • Case Example: James, a 47-year-old security guard, often worked night shifts. He noticed that after prolonged exposure to dim lighting, his vision would blur and his eyes felt strained. His eye doctor confirmed that his narrow-angle glaucoma symptoms were worsened by the low-light conditions.

Prevalence of Narrow-Angle Glaucoma by Age Group

This chart presents the prevalence of narrow-angle glaucoma across different age groups, highlighting the increasing risk with age.

Symptoms of Narrow-Angle Glaucoma

Symptoms can vary depending on whether the condition is chronic (slow-developing) or acute (sudden and severe).

Acute Narrow-Angle Glaucoma (Medical Emergency)

• Severe eye pain – Feels like intense pressure inside the eye, similar to a deep, unrelenting headache localized in the eye region.
• Blurred vision – Objects may appear smeared or out of focus, making it hard to read or recognize faces.
• Headache – Often starts around the forehead or temples, worsening with time and eye movement.
• Nausea and vomiting – A sensation of dizziness or queasiness, much like motion sickness, which can escalate to vomiting.
• Seeing halos around lights – Light sources, such as street lamps or car headlights, may have glowing rings around them, making night vision particularly challenging.
• Redness in the eye – The affected eye may appear bloodshot due to inflammation, with visible veins becoming more pronounced.

Chronic Narrow-Angle Glaucoma

• Gradual vision loss – Peripheral vision may begin to fade first, making it feel like objects or movement at the sides are harder to detect.
• Mild headaches – Often subtle and persistent, particularly after reading, watching screens, or being in dim lighting for prolonged periods.
• Occasional blurry vision – Vision may become temporarily unclear, especially in low-light conditions, but improves after resting the eyes.

Reyus Mammadli, Health Care Advisor states, that since chronic narrow-angle glaucoma can develop without noticeable symptoms, regular eye exams are crucial for early detection.

Diagnosis

Eye care professionals diagnose narrow-angle glaucoma through a series of tests, each with different levels of accuracy and costs:

• Gonioscopy – A special lens is used to examine the drainage angle.
  • Procedure: The doctor places numbing drops in the eye and uses a mirrored contact lens to assess the angle between the iris and cornea.
  • Accuracy: Rated 9/10. Provides a clear view of the drainage angle to detect narrowing.
  • Cost: Typically ranges from $50 to $150 per exam.
• Tonometry – Measures intraocular pressure (IOP).
  • Procedure: A small probe gently touches the eye or a puff of air is directed at the cornea to gauge pressure.
  • Accuracy: Rated 8/10. Effective for detecting elevated eye pressure but may need repeat testing for confirmation.
  • Cost: Usually between $20 and $100 per test.
• Optical Coherence Tomography (OCT) – Provides detailed imaging of the eye structures.
  • Procedure: Uses a non-invasive laser scan to capture cross-sectional images of the retina and optic nerve.
  • Accuracy: Rated 9.5/10. Highly precise in detecting early structural damage.
  • Cost: Can range from $100 to $300 per eye.
• Visual Field Test – Checks for peripheral vision loss.
  • Procedure: The patient looks into a machine and presses a button when they see a light flash in different areas.
  • Accuracy: Rated 8.5/10. Useful for tracking vision changes over time.
  • Cost: Generally between $50 and $150 per session.

Treatment Options

Treatment depends on the severity of the condition. The goal is to lower intraocular pressure and prevent optic nerve damage.

Patient Satisfaction Rates for Different Glaucoma Treatments

This chart compares patient satisfaction rates for different glaucoma treatments, indicating higher satisfaction levels for surgery and laser treatments compared to medication.

1. Laser Peripheral Iridotomy (LPI)

• Procedure: A laser creates a small hole in the iris to improve fluid drainage.
• Accuracy: Rated 9/10. Highly effective in preventing acute attacks.
• Cost: Typically ranges from $500 to $1,500 per eye.
• What to Expect: The procedure takes about 5-10 minutes per eye, with mild discomfort and temporary blurry vision.
• Procedure: A laser creates a small hole in the iris to improve fluid drainage.
• Effectiveness: Rated 8/10. Effective in preventing acute attacks but may not fully control IOP in all cases.
• Cost: Typically ranges from $500 to $1,500 per eye.
• What to Expect: The procedure takes about 5-10 minutes per eye, with mild discomfort and temporary blurry vision.

2. Medications

• Types:
  • Eye drops such as prostaglandin analogs, beta-blockers, or carbonic anhydrase inhibitors help reduce IOP.
  • Oral medications like acetazolamide may be prescribed in acute cases.
• Accuracy: Rated 7/10. Works well for many patients but requires consistent use.
• Cost: Prescription eye drops range from $20 to $200 per month.
• What to Expect: Medications must be used daily. Some may cause mild side effects like eye irritation, dryness, or changes in taste.
• Types:
  • Eye drops such as prostaglandin analogs, beta-blockers, or carbonic anhydrase inhibitors help reduce IOP.
  • Oral medications like acetazolamide may be prescribed in acute cases.
• Effectiveness: Rated 7/10. Works well for many patients but requires consistent use.
• Cost: Prescription eye drops range from $20 to $200 per month.

3. Surgical Procedures

• Trabeculectomy:
  • Procedure: Creates a new drainage pathway for fluid, reducing intraocular pressure.
  • Accuracy: Rated 9/10. One of the most effective surgical treatments but carries some risk of infection and scarring.
  • Cost: Ranges from $3,000 to $6,000 per eye.
  • What to Expect: Recovery takes several weeks, requiring follow-up visits to monitor healing and IOP stability.
• Lens Extraction (Clear Lens Extraction or Cataract Surgery):
  • Procedure: The thickened natural lens is removed and replaced with an artificial one, opening the drainage angle and reducing IOP.
  • Accuracy: Rated 9/10. Especially beneficial for patients with both cataracts and narrow angles.
  • Cost: Between $3,500 and $5,000 per eye.
  • What to Expect: Recovery takes 1-2 weeks, with mild discomfort and improved vision as healing progresses.
• Trabeculectomy: Creates a new drainage pathway for fluid, reducing intraocular pressure.
• Lens Extraction (Clear Lens Extraction or Cataract Surgery): Removing a thickened lens can open the drainage angle, reducing IOP.

Editorial Advice

Narrow-angle glaucoma is a silent but dangerous condition that requires prompt medical attention. If you experience sudden eye pain or vision changes, seek emergency care immediately. For those at risk, regular eye exams can be a sight-saving decision.