Acute glaucoma causes. Acute Angle-Closure Glaucoma: Causes, Symptoms, and Treatment

21.08.202327.06.2023 by alexxlab

What are the main causes of acute angle-closure glaucoma. How does acute angle-closure glaucoma present clinically. What are the risk factors for developing acute angle-closure glaucoma. How is acute angle-closure glaucoma diagnosed and treated. What complications can occur if acute angle-closure glaucoma is left untreated.

Содержание

Understanding Acute Angle-Closure Glaucoma

Acute angle-closure glaucoma is a serious ocular emergency characterized by a rapid increase in intraocular pressure due to obstruction of aqueous humor outflow. This condition can lead to severe vision loss if not promptly diagnosed and treated. To fully grasp the complexities of this condition, it’s essential to explore its underlying mechanisms, presentation, and management strategies.

Pathophysiology of Acute Angle-Closure Glaucoma

The pathophysiology of acute angle-closure glaucoma is primarily rooted in the structural anatomy of the eye’s anterior chamber. The key factor predisposing individuals to this condition is a shallower angle between the iris and cornea. This anatomical configuration sets the stage for a cascade of events that can rapidly escalate to an acute glaucoma attack.

The Mechanism of Angle Closure

In acute angle-closure glaucoma, several factors contribute to the obstruction of aqueous humor outflow:

Pupillary block: The iris and lens come into close contact, impeding the flow of aqueous humor from the posterior to the anterior chamber.
Iris bowing: The pressure differential between chambers causes the iris to bow forward, further narrowing the angle.
Angle obstruction: As the angle narrows, the trabecular meshwork becomes blocked, preventing proper drainage of aqueous humor.

Is pupillary dilation a trigger for acute angle-closure glaucoma? Indeed, pupillary dilation can precipitate an acute attack by increasing iris-lens contact and exacerbating pupillary block. This explains why attacks may occur in dimly lit environments or after the use of certain medications that cause pupil dilation.

Clinical Presentation and Symptoms

Recognizing the signs and symptoms of acute angle-closure glaucoma is crucial for timely intervention. The presentation is typically dramatic and unmistakable, often described as one of the most painful ocular conditions.

Key Symptoms

Sudden onset of severe unilateral eye pain or headache
Blurred or decreased vision
Perception of rainbow-colored halos around bright lights
Nausea and vomiting
Eye redness

What physical exam findings are characteristic of acute angle-closure glaucoma? On examination, clinicians will typically observe:

A fixed, mid-dilated pupil
A hazy or cloudy cornea
Marked conjunctival injection (redness)
Significantly elevated intraocular pressure (often >50 mmHg)

Risk Factors and Epidemiology

Understanding the risk factors for acute angle-closure glaucoma can aid in identifying individuals at higher risk and potentially preventing attacks through prophylactic measures.

Demographic Factors

Several demographic characteristics are associated with an increased risk of acute angle-closure glaucoma:

Age: The average age at presentation is 60 years, with increasing prevalence thereafter.
Gender: Women are affected more frequently than men, with a 4:1 ratio.
Race: Southeast Asians, Chinese, and Inuit populations have a higher incidence, while it is less common in black populations.
Family history: Ocular anatomic features predisposing to angle closure are often inherited.

Why does age play a role in the development of acute angle-closure glaucoma? The increasing size of the lens with age contributes to a shallower anterior chamber, predisposing older individuals to angle closure.

Diagnostic Approach and Evaluation

Prompt and accurate diagnosis of acute angle-closure glaucoma is essential for preserving vision and preventing complications. The diagnostic process typically involves a combination of clinical examination and specialized tests.

Key Diagnostic Steps

Patient history: Gathering information about the onset and nature of symptoms.
Visual acuity assessment: To determine the extent of vision impairment.
Slit-lamp examination: To evaluate the anterior chamber depth and angle.
Tonometry: To measure intraocular pressure.
Gonioscopy: To directly visualize the angle structures (if corneal clarity permits).
Ophthalmoscopy: To assess the optic nerve for signs of damage.

How does gonioscopy aid in the diagnosis of acute angle-closure glaucoma? Gonioscopy allows direct visualization of the anterior chamber angle, confirming the presence of angle closure and helping to differentiate between acute and chronic forms of angle-closure glaucoma.

Management and Treatment Strategies

The management of acute angle-closure glaucoma is a medical emergency requiring immediate intervention to lower intraocular pressure and prevent permanent vision loss. Treatment typically involves a combination of medical and surgical approaches.

Initial Medical Management

The primary goal of initial treatment is to rapidly reduce intraocular pressure. This may include:

Topical beta-blockers and alpha-2 agonists to decrease aqueous production
Topical and oral carbonic anhydrase inhibitors
Hyperosmotic agents like mannitol or glycerol to dehydrate the vitreous
Analgesics for pain relief
Antiemetics to control nausea and vomiting

What role do miotics play in the treatment of acute angle-closure glaucoma? Once the intraocular pressure begins to decrease, miotics like pilocarpine can be used to constrict the pupil and help pull the iris away from the angle, potentially breaking the attack.

Definitive Treatment

Once the acute attack is controlled, definitive treatment is necessary to prevent recurrence:

Laser peripheral iridotomy: Creates a small hole in the iris to equalize pressure between the anterior and posterior chambers, eliminating pupillary block.
Surgical iridectomy: A surgical alternative to laser treatment, creating a similar opening in the iris.
Lens extraction: In some cases, removing the lens (cataract surgery) can help deepen the anterior chamber and resolve angle closure.

Complications and Prognosis

Acute angle-closure glaucoma can lead to severe complications if not promptly treated. Understanding these potential outcomes underscores the importance of rapid intervention.

Potential Complications

Permanent vision loss due to optic nerve damage
Chronic angle-closure glaucoma
Peripheral anterior synechiae (adhesions between the iris and cornea)
Cataract formation
Corneal decompensation

Can acute angle-closure glaucoma cause irreversible vision loss? Yes, if left untreated, the sustained high intraocular pressure can cause irreversible damage to the optic nerve, leading to permanent vision loss. This emphasizes the critical nature of prompt diagnosis and treatment.

Prevention and Prophylaxis

While not all cases of acute angle-closure glaucoma can be prevented, certain measures can be taken to reduce the risk in susceptible individuals.

Preventive Strategies

Regular eye examinations: Particularly important for individuals with risk factors.
Prophylactic laser iridotomy: May be recommended for patients with very narrow angles.
Awareness of triggers: Educating at-risk patients about situations that may precipitate an attack (e.g., dim lighting, certain medications).
Genetic counseling: For families with a history of angle-closure glaucoma.

How effective is prophylactic laser iridotomy in preventing acute angle-closure glaucoma? Prophylactic laser iridotomy has been shown to be highly effective in preventing acute attacks in individuals with anatomically narrow angles, significantly reducing the risk of angle closure.

The Role of the Interprofessional Team

Managing acute angle-closure glaucoma requires a coordinated effort from various healthcare professionals. An interprofessional approach ensures comprehensive care and optimal outcomes for patients.

Key Team Members and Their Roles

Ophthalmologists: Provide specialized diagnosis, treatment, and surgical interventions.
Emergency physicians: Often the first point of contact, initiating early treatment and facilitating timely referral.
Optometrists: Play a crucial role in early detection and referral of at-risk patients.
Nurses: Assist in patient care, medication administration, and education.
Pharmacists: Ensure appropriate medication selection and dosing, and educate patients on proper use of eye drops.

How does collaboration between emergency physicians and ophthalmologists improve outcomes in acute angle-closure glaucoma? Close collaboration ensures rapid initiation of treatment in the emergency department, followed by timely definitive management by an ophthalmologist, maximizing the chances of preserving vision and preventing complications.

Future Directions and Research

As our understanding of acute angle-closure glaucoma evolves, ongoing research aims to improve prevention, diagnosis, and treatment strategies.

Emerging Areas of Research

Advanced imaging techniques: Utilizing high-resolution OCT and AI-assisted analysis for earlier detection of at-risk eyes.
Genetic studies: Identifying genetic markers associated with increased risk of angle closure.
Novel therapeutic approaches: Developing medications that can rapidly and safely lower intraocular pressure during acute attacks.
Minimally invasive surgical techniques: Exploring new procedures that can effectively prevent angle closure with reduced risk and faster recovery.

What potential does genetic research hold for the management of acute angle-closure glaucoma? Genetic studies may lead to the development of predictive tests, allowing for earlier identification of at-risk individuals and more targeted preventive strategies.

Acute angle-closure glaucoma remains a challenging and potentially devastating ocular emergency. However, with increased awareness, prompt recognition, and advances in treatment modalities, the prognosis for affected individuals continues to improve. The key to successful management lies in rapid intervention, coordinated care, and ongoing research to enhance our understanding and treatment of this complex condition.

Acute Closed Angle Glaucoma – StatPearls

Babak Khazaeni; Leila Khazaeni.

Author Information and Affiliations

Last Update: January 2, 2023.

Continuing Education Activity

Acute angle-closure glaucoma is an ocular emergency that results from a rapid increase in intraocular pressure due to outflow obstruction of aqueous humor. Several factors lead to the obstruction in acute angle-closure glaucoma, but the major predisposing factor is the structural anatomy of the anterior chamber, leading to a shallower angle between the iris and the cornea. Acute angle-closure glaucoma presents as a sudden onset of severe unilateral eye pain or a headache associated with blurred vision, rainbow-colored halos around bright lights, nausea, and vomiting. The physical exam will reveal a fixed midpoint pupil and a hazy or cloudy cornea with marked conjunctival injection. This activity reviews the evaluation and management of patients with acute angle-closure glaucoma and highlights the role of the interprofessional team in managing patients with this condition.

Objectives:

Describe the pathophysiology of acute angle-closure glaucoma.
Summarize how a patient with acute angle-closure glaucoma is likely to present.
Identify the critical immediate steps to take when managing a patient with acute angle-closure glaucoma.
Outline the role of a collaborative interprofessional team in providing well-coordinated care to patients presenting with acute angle-closure glaucoma.

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Introduction

Glaucoma is a set of ocular disorders often defined by increased intraocular pressures leading to optic neuropathy and vision loss if untreated.[1] Glaucoma has traditionally been classified as open-angle or closed-angle and as primary or secondary. The angle refers to the angle between the iris and the cornea in the anterior chamber, which can become structurally obstructed. By definition, primary glaucomas are not associated with known ocular or systemic disorders and usually affect both eyes. Secondary glaucomas are associated with ocular or systemic disorders and are often unilateral. Acute angle-closure glaucoma is a subset of primary angle-closure glaucoma.

The commonly accepted range for intraocular pressure is 10 to 22 mmHg. Three factors that affect the intraocular pressure are the rate of production of aqueous humor by the ciliary body, the resistance to aqueous outflow through the trabecular meshwork and Schlemm’s canal, and the episcleral venous pressure. The normal flow of aqueous humor starts in the ciliary body, goes through the pupil, and out through the trabecular meshwork and Schlemm’s canal in the angle of the anterior chamber. In acute angle-closure glaucoma, intraocular pressure increases rapidly due to outflow obstruction of the aqueous humor. Several factors lead to the obstruction in acute angle-closure glaucoma, but the major predisposing factor is the structural anatomy of the anterior chamber leading to a shallower angle.[2][3]

Etiology

Blockage to the flow of aqueous humor occurs due to a number of predisposing anatomic variations. These variations include a shallower anterior chamber, lens size, anterior location of the iris-lens diaphragm, and a narrow entrance to the anterior chamber angle. The shallower anterior chamber angle leads to a large area of the iris and lens being in contact with each other, slowing the flow of aqueous humor from the posterior chamber to the anterior chamber. This, in turn, leads to a pressure difference between the chambers called a pupillary block.[4]

The pupillary block causes bowing of the iris, which narrows the angle of the anterior chamber further. This cycle will perpetuate increasing intraocular pressures leading to the clinical presentation of acute angle-closure glaucoma.

Epidemiology

There are several risk factors for acute angle-closure glaucoma, including age, gender, race, and family history.[5]

Age: The average age at presentation is 60, and prevalence increases thereafter. This is felt to be due to the increasing size of the lens with age.
Gender: There is a 4 to 1 ratio of the incidence of angle-closure glaucoma in women versus men.
Race: Angle-closure glaucoma is more common in Southeast Asians, Chinese, and Eskimos. It is uncommon in black populations. In whites, acute angle-closure glaucoma accounts for 6% of all glaucoma diagnoses.[6]
Family history: Ocular anatomic features are inherited.

Pathophysiology

An acute attack of angle-closure glaucoma is precipitated by pupillary dilatation, leading to increasing iris and lens contact increasing the pupillary block.[7] The increasing pupillary block leads to bulging of the iris, acutely closing the angle between the iris and cornea, thus obstructing the aqueous humor outflow tract. The intraocular pressure rises acutely, leading to symptomology.

History and Physical

Acute angle-closure glaucoma presents as a sudden onset of severe unilateral eye pain or a headache associated with blurred vision, rainbow-colored halos around bright lights, nausea, and vomiting. The physical exam will reveal a fixed midpoint pupil and a hazy or cloudy cornea with marked conjunctival injection (most prominent at the limbus). Intraocular pressure will be elevated and can be as high as 60 to 80 mm Hg in an acute attack. A mild amount of aqueous flare and cells may be seen. The optic nerve may also be swollen during an acute attack.[8][9]

Evaluation

Measuring elevated intraocular pressure is diagnostic. There is no need for any imaging studies. A basic metabolic panel should be checked if osmotic agents are used in the treatment regime. A gonioscopic examination by an ophthalmologist to verify angle-closure makes the definitive diagnosis. Gonioscopy of the unaffected eye will reveal a narrow occludable angle given the anatomic predisposing factors to acute angle-closure glaucoma (See other issues for further discussion). Glaucomflecken (grey-white opacities on the anterior lens capsule) may be visible if previous attacks of angle-closure glaucoma have occurred. [10]

Treatment / Management

The medical treatment for acute angle-closure glaucoma aims to decrease the intraocular pressure by blocking the production of aqueous humor, increasing the outflow of aqueous humor, and reducing the volume of the aqueous humor.[11][12]

Initial medical therapy includes a combination of the following medications:

Intravenous acetazolamide 500 mg to block the production of aqueous humor.
Intravenous mannitol 1 to 2 grams/kg can be given (if there is no contraindication) to rapidly reduce the volume of aqueous humor.
Topical beta-blocker (timolol 0.5%) one drop to block the production of aqueous humor.
Topical alpha 2-agonist (apraclonidine 1%) one drop to block the production of aqueous humor.
Topical pilocarpine 1% to 2% one drop every 15 minutes for two doses once intraocular pressure is below 40 mm Hg to increase the outflow of aqueous humor. This is not effective at higher pressures due to pressure-induced ischemic paralysis of the iris.

Intraocular pressure needs to be checked every hour.

Definitive treatment is peripheral iridectomy after the acute episode subsides. Laser iridectomy is the treatment of choice. Surgical iridectomy is indicated when laser iridectomy can not be accomplished. Iridectomy relieves the pupillary block as the pressure between the posterior and anterior chamber approaches zero by allowing the flow of aqueous humor through a different route. Iridectomy should be as peripheral as possible and covered by the eyelid to avoid monocular diplopia through this second hole in the pupil.[13]

Differential Diagnosis

Allergic conjunctivitis
Bacterial conjunctivitis (pink eye)
Viral conjunctivitis
Drug-induced glaucoma
Malignant glaucoma
Neovascular glaucoma
Phacomorphic glaucoma
Senile cataract (age-related cataract)
Lens subluxation[14]
Migraine headache[15]
Cluster headache
Suprachoroidal hemorrhage

Prognosis

The prognosis depends on early detection and prompt treatment of acute closed-angle glaucoma. A study conducted on 116 cases of acute angle-closure glaucoma concluded that the delay in presentation and the time taken to end the acute episode was the most important factor in determining the final outcome of these patients. High intraocular pressure was less effective in determining the long-term prognosis of this condition.[16]

Complications

If acute closed-angle glaucoma is not detected and treated in its initial stages, it can lead to temporary loss of vision or blindness. There is a loss of peripheral vision, followed by a loss of central vision. There can be a significant increase in IOP in patients with peripheral patent iridotomy and a flat anterior chamber. This condition is called malignant glaucoma. This condition is difficult to treat and progressively leads to blindness.[17]

Deterrence and Patient Education

Patients with a history of acute angle-closure glaucoma should avoid dim light. Pupils dilate in response to dim light, further narrowing the iridocorneal angle. Patients with hypermetropia are at an increased risk of developing angle-closure glaucoma.

Pearls and Other Issues

An untreated opposite eye has a 40% to 80% chance of developing an acute attack of angle-closure glaucoma over 5 to 10 years as it shares the same anatomic predisposing factors as the first eye.[18] Hence peripheral iridectomy should be performed in the other eye as well as the affected eye.

The gender and ethnicity predisposing factors to acute angle-closure glaucoma hint at a genetic predisposition to the disease in certain populations. Recent large-scale studies have shown a clear association to several genes and genetic loci with primary open-angle glaucoma, but evidence for acute angle-closure glaucoma is sparse. So far, only one study has shown a genetic locus on Chromosome 11 that can cause acute angle-closure glaucoma. Studies have been conducted on possible therapeutic targets in patients with early-onset glaucoma based on molecular and cellular events caused by MYOC, OPTN, and TBK1 mutations. [19]

Enhancing Healthcare Team Outcomes

Acute angle-closure glaucoma is best managed by an interprofessional team, including an ophthalmologist, family clinician, an ophthalmology nurse, and the pharmacist. After managing the emergency with eye drops, the patient should be scheduled for an iridectomy. Clinicians need to be aware that the other eye is also at risk for acute angle-closure glaucoma, and prophylactic surgery is recommended.

The outcomes for patients with acute angle-closure glaucoma are good following treatment. However, delay in treatment can lead to damage to the optic nerve and vision loss.

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References

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: Disclosure: Babak Khazaeni declares no relevant financial relationships with ineligible companies.
: Disclosure: Leila Khazaeni declares no relevant financial relationships with ineligible companies.