Acute Angle-Closure Glaucoma

Acute angle-closure glaucoma occurs when the iris bulges forward and seals off the trabecular meshwork from the anterior chamber preventing aqueous humour from being able to drain away, leading to a continual buildup of IOP

Aetiology

Anatomical Predisposition

  • Shallow anterior chamber
  • Narrow iridocorneal angle
  • Thick or anteriorly positioned crystalline lens
  • Short axial length (hyperopic eyes)

Precipitating Factors

  • Pupillary dilation (dark environment, emotional stress)
  • Mydriatic or anticholinergic drugs
  • Sympathomimetic agents
  • Systemic medications (e.g., antidepressants, antihistamines)

Clinical presentation

Symptoms

  • Sudden onset severe ocular pain
  • Blurred vision with halos around lights
  • Headache
  • Nausea and vomiting

Signs

  • Markedly elevated IOP (often >40 mmHg)
  • Conjunctival injection (ciliary flush)
  • Corneal edema causing hazy cornea
  • Shallow anterior chamber
  • Mid-dilated, sluggish or non-reactive pupil
  • Decreased visual acuity
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Investigations

Clinical Examination

  • Measurement of intraocular pressure (tonometry)
  • Slit-lamp examination
  • Gonioscopy (after acute attack resolution)
  • Funduscopy (often limited during acute phase)
    • Nasalization
    • Bayonetting
    • C/D ratio > 0.5
    • Exposed lamina cribrosa
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Ancillary Tests

  • Anterior segment optical coherence tomography (AS-OCT)
  • Ultrasound biomicroscopy (UBM) in selected cases

Management

Acute Medical Management

  • Systemic carbonic anhydrase inhibitors (first-line in emergency settings)
    • Acetazolamide PO/IV 500mg loading dose + PO 125-250mg 4x1
  • Topical beta-blockers
    • Timolol 0.25%-0.5% ED 1x1
  • Miotics after IOP < 40 mmHg
    • Pilocarpine 2% ED 1x1
  • Topical alpha-agonists
  • Topical carbonic anhydrase inhibitors
  • Hyperosmotic agentsif
    • IOP remains markedly elevated (>40–50 mmHg) or severe corneal edema.
    • Mannitol 20% 1-2 g/kg IV
  • Topical corticosteroids to reduce inflammation

Definitive Treatment

  • Laser Peripheral Iridotomy (LPI): treatment of choice
  • Surgical iridectomy if laser is not feasible
  • Prophylactic LPI in the fellow eye