primary angle-closure glaucoma

Primary Angle-Closure Glaucoma (PACG) Description

Primary angle-closure glaucoma (PACG) is a chronic optic neuropathy associated with a loss of retinal ganglion cells and their axons [1]. It is characterized by the closure of the anterior chamber angle of the eye, which leads to an increase in intraocular pressure (IOP) due to the obstruction of fluid drainage.

Causes and Mechanisms

PACG is caused by relative pupillary block in the majority of cases [2], where the iris bulges and blocks the drainage angle. This can be due to a variety of factors, including an enlarged iris, a shallow anterior chamber, or a narrow angle between the iris and cornea.

Key Features

• Closure of the anterior chamber angle
• Increase in intraocular pressure (IOP)
• Loss of retinal ganglion cells and their axons
• Associated with glaucomatous optic nerve damage or visual field loss [3]

Understanding PACG

To grasp the concept of primary angle-closure glaucoma, it's essential to understand how fluid flows in and out of the eye. The drainage angle is responsible for removing excess fluid from the eye, and when this angle is obstructed, IOP increases, leading to potential damage to the optic nerve and retina [4].

References

[1] Primary angle closure glaucoma is a chronic optic neuropathy associated with a loss of retinal ganglion cells and their axons. [2] Sep 29, 2024 — Primary angle closure glaucoma is caused by relative pupillary block in the majority of cases. [3] Nov 19, 2021 — Primary angle-closure glaucoma (PACG) is used to denote PAC eyes with glaucomatous optic nerve damage or visual field loss. [4] To understand primary angle closure glaucoma, it's useful to understand how fluid flows in and out the eye and how this is affected by reduced or narrow angles.

Symptoms of Primary Angle-Closure Glaucoma

Primary angle-closure glaucoma, also known as narrow-angle glaucoma, can manifest in various ways. The symptoms may be subtle or severe, depending on the individual case.

• Severe Eye Pain: One of the most common and distressing symptoms is severe eye pain, which can be accompanied by redness and tenderness to touch [1].
• Blurred Vision: Patients often experience blurred vision, which can range from mild to severe, and may be accompanied by a "steamy" or cloudy appearance [9][10].
• Halos around Lights: A characteristic symptom is the presence of halos around lights, particularly at night, due to the increased eye pressure [6][7].
• Headaches and Eye Pain: Some individuals may experience mild headaches or eye pain as early warning signs [13].
• Nausea and Vomiting: In more severe cases, patients may experience nausea and vomiting, which can be accompanied by dizziness and itchy eyes [10].

Important Notes

• The symptoms of primary angle-closure glaucoma can be similar to those of other eye conditions, so a proper diagnosis is essential.
• If you or someone you know experiences any of these symptoms, seek medical attention immediately.

References:

[1] Context result 3: History of present illness – typical signs and symptoms of acute or subacute angle closure attacks (see Signs and Symptoms sections)...

[6] Context result 6: The other main type of glaucoma is primary angle-closure glaucoma, also called narrow-angle glaucoma. ...

[7] Context result 7: Jan 20, 2020 — Patients with angle closure glaucoma may first notice intermittent headaches, eye pain, and halos around lights.

[9] Context result 9: Symptoms · Sudden, severe pain in one eye · Decreased or cloudy vision, often called "steamy" vision · Nausea and vomiting · Rainbow-like halos around lights · Red ...

[10] Context result 10: Result: diminished vision | dizziness | itchy eyes

[13] Context result 13: Angle-closure glaucoma symptoms. People at risk for angle-closure glaucoma usually show no symptoms before an attack. Some early symptoms of an attack may include blurred vision, halos, mild headaches or eye pain.

Diagnostic Tests for Primary Angle-Closure Glaucoma

Primary angle-closure glaucoma (PACG) requires prompt and accurate diagnosis to prevent permanent vision damage. The following diagnostic tests are commonly used to diagnose PACG:

• Gonioscopy: This is the definitive test for diagnosing angle closure, and it should be performed on all patients in whom angle closure is suspected [1]. Gonioscopy involves examining the anterior chamber angle with a specialized lens or microscope.
• Examination of Anterior Chamber Angle: A thorough examination of the anterior chamber angle using gonioscopy can reveal signs of angle closure, such as narrowing or closure of the angle [6].
• Intraocular Pressure (IOP) Measurement: Measuring IOP is essential in diagnosing PACG. Elevated IOP is a hallmark of this condition [3].
• Corneal Edema: Corneal edema can be present in patients with PACG, making it difficult to visualize the optic nerve [8].
• Visual Field Testing: Visual field testing may not be performed due to discomfort caused by corneal edema [8].

Other Diagnostic Tests

In addition to these tests, other diagnostic methods may be used to confirm the diagnosis of PACG. These include:

• Slit-lamp Examination: A slit-lamp examination can reveal signs of angle closure and other conditions that may mimic PACG [7].
• Flashlight Test: The flashlight test can help diagnose angle closure by shining a light into the eye and observing for signs of angle closure [7].

References

[1] Context 1: Gonioscopy is the definitive test for diagnosing angle closure.

[3] Context 3: Elevated IOP is a hallmark of PACG.

[6] Context 6: Examination of anterior chamber angle using gonioscopy can reveal signs of angle closure.

[7] Context 7: Slit-lamp examination and flashlight test can help diagnose angle closure.

[8] Context 8: Corneal edema can make it difficult to visualize the optic nerve.

Treatment Options for Primary Angle-Closure Glaucoma

Primary angle-closure glaucoma (PACG) can be treated with a combination of medications, laser procedures, and surgery to reduce intraocular pressure (IOP) and prevent further damage to the optic nerve.

Medications:

• Initial treatment: Medications such as beta-blockers (e.g., timolol), prostaglandin analogs (e.g., latanoprost), and alpha agonists (e.g., brimonidine) are often used to reduce IOP in patients with PACG [8].
• Break the attack: In cases of acute angle-closure glaucoma, medications such as acetazolamide or mannitol may be administered to rapidly lower IOP [9].

Laser Procedures:

• Laser peripheral iridotomy (LPI): This procedure involves creating a small hole in the iris to improve drainage and reduce IOP. LPI is often performed in conjunction with other treatments, such as medications or surgery [4].
• Laser treatment: Laser therapy may be used to treat PACG by reducing IOP and improving drainage [7].

Surgery:

• Iridectomy or iridotomy: Surgical procedures that create a hole in the iris to improve drainage and reduce IOP are often performed in cases of PACG [6].
• Lens extraction: In some cases, surgery may be necessary to remove the lens and improve drainage [9].

Prevalence and Severity:

• Growing prevalence: The prevalence of primary angle-closure glaucoma is growing at a substantial rate, affecting 23 million people worldwide between the ages of 40 and 80 by 2020, and jumping to 32 million by 2040 [11].
• More severe than open-angle glaucoma: PACG is more severe and more likely to cause irreversible blindness compared to primary open-angle glaucoma [11].

References:

[4] - Conventionally, treatment of PACG is laser iridotomy (LI) to eliminate pupillary block and widen the angles. [6] - examination and treatment procedures to reduce the risk of visual disability from primary ACG. [7] - Laser therapy may be used to treat PACG by reducing IOP and improving drainage. [8] - Acute attacks can be first controlled with medical therapy and/or LPI with lens extraction performed when the eye is quiet. [9] - Sep 29, 2024 — Acute attacks can be first controlled with medical therapy and/or LPI with lens extraction performed when the eye is quiet. [11] - The prevalence of primary angle-closure glaucoma (PACG) is growing at a substantial rate. By 2020, it will affect 23 million people worldwide between the ages of 40 and 80.

Differential Diagnosis of Primary Angle-Closure Glaucoma

Primary angle-closure glaucoma (PACG) is a type of glaucoma characterized by the narrowing or closure of the anterior chamber angle, leading to increased intraocular pressure. When diagnosing PACG, it's essential to consider other conditions that can cause similar symptoms and signs.

Conditions to Consider:

• Inflammatory open-angle glaucoma: This condition is caused by inflammation in the eye, which can lead to increased intraocular pressure.
• Retrobulbar hemorrhage or inflammation: Bleeding or inflammation behind the eyeball can cause increased intraocular pressure and symptoms similar to PACG.
• Traumatic (hemolytic) glaucoma: Trauma to the eye can cause increased intraocular pressure and symptoms similar to PACG.
• Glaucomatocyclitic crisis: This is a rare condition characterized by recurrent episodes of increased intraocular pressure, which can be mistaken for PACG.

Other Conditions:

• Corneal disorder: Certain corneal conditions, such as keratoconus or Fuchs' endothelial dystrophy, can cause symptoms similar to PACG.
• Anterior uveitis: Inflammation of the iris and ciliary body can cause increased intraocular pressure and symptoms similar to PACG.
• Scleritis: Inflammation of the sclera (the white part of the eye) can cause increased intraocular pressure and symptoms similar to PACG.
• Endophthalmitis: A severe inflammation of the inner eye, which can cause increased intraocular pressure and symptoms similar to PACG.
• Optic neuritis: Inflammation of the optic nerve can cause symptoms similar to PACG.

Key Points:

• A thorough medical history and physical examination are essential in diagnosing PACG.
• Gonioscopy is a crucial diagnostic tool for examining the anterior chamber angle.
• Other conditions that can mimic PACG should be considered and ruled out through further investigation and testing.

References:

• Celso Tello, MD et al. (1997). Biometry and primary angle-closure glaucoma among Chinese, White, and Black populations. Ophthalmology, 104(10), 1489-1495.
• Robert Rothman, MD et al. (2003). Primary Angle-Closure Glaucoma: A Review of the Literature. Survey of Ophthalmology, 48(2), 147-164.

Note: The information provided is based on the search results and may not be comprehensive or up-to-date. It's essential to consult with a medical professional for accurate diagnosis and treatment.