Acute Angle-Closure Glaucoma

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | References

Definition

Acute angle-closure glaucoma is a medical emergency characterised by a sudden increase in intraocular pressure (IOP) due to the closure of the anterior chamber angle, which obstructs aqueous humour outflow.

Aetiology

Acute angle-closure glaucoma can be caused by factors that lead to a sudden blockage of the drainage angle in the eye, including:

• Anatomical predisposition (e.g., shallow anterior chamber)
• Pupil dilation (e.g., in low light conditions or use of certain medications)
• Thickening of the lens with age

Pathophysiology

The anterior chamber angle, formed between the iris and cornea, is where aqueous humour drains out of the eye. In acute angle-closure glaucoma, this angle becomes blocked, leading to a rapid increase in intraocular pressure. This can cause optic nerve damage and, if not treated promptly, permanent vision loss.

Risk Factors

• Age (older adults)
• Family history of glaucoma
• Hyperopia (farsightedness)
• Asian descent
• Female gender

Signs and Symptoms

Common signs and symptoms of acute angle-closure glaucoma include:

• Severe eye pain
• Red eye
• Blurred vision
• Halos around lights
• Headache
• Nausea and vomiting

Investigations

• Clinical history and physical examination
• Measurement of intraocular pressure (tonometry)
• Gonioscopy to examine the anterior chamber angle
• Slit-lamp examination to assess the anterior segment of the eye
• Ophthalmoscopy to examine the optic nerve head

Management

Primary Care Management

• Immediate referral to an ophthalmologist: Acute angle-closure glaucoma is a medical emergency
• Secondary care management: Examples of interventions to lower IOP:
  • Oral or intravenous acetazolamide
  • Topical beta-blockers
  • Topical alpha agonists

Specialist Management

• Medical therapy:
  • Topical pilocarpine to constrict the pupil and open the angle
  • Intravenous mannitol to reduce IOP
  • Systemic carbonic anhydrase inhibitors (e.g., acetazolamide)
• Surgical intervention:
  • Laser peripheral iridotomy to create an opening in the iris and allow aqueous humour to flow through the trabecular meshwork
  • Trabeculectomy or other filtering surgeries if necessary
• Regular follow-up to monitor IOP and optic nerve health

References

1. NICE. (2024). Glaucoma: Diagnosis and Management. Retrieved from NICE
2. NHS. (2023). Acute Angle-Closure Glaucoma. Retrieved from NHS
3. British Medical Journal (BMJ). (2022). Acute Angle-Closure Glaucoma: Diagnosis and Management. Retrieved from BMJ
4. American Academy of Ophthalmology (AAO). (2021). Clinical Practice Guidelines: Acute Angle-Closure Glaucoma. Retrieved from AAO

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