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Acute Angle-Closure Glaucoma

CRITICAL — Glaucoma

Symptoms

Presentation

  • Sudden onset of severe eye pain and frontal headache.
  • Blurred vision and colored halos around lights.
  • Systemic symptoms: Nausea and vomiting (often misdiagnosed as GI illness or migraine).

Clinical Findings

Primary diagnostic signs

  • Acutely elevated intraocular pressure (IOP), often 40–80 mmHg.
  • Closed angle on gonioscopy in the involved eye.
  • Fixed, mid-dilated pupil with a shallow anterior chamber.

Anterior segment

  • Microcystic corneal edema and conjunctival injection (ciliary flush).
  • AC cell and flare or iridescent particles.

Signs of prior attacks

  • Glaukomflecken: Small anterior subcapsular lens opacities.
  • Iris stromal atrophy.

Fellow eye

  • Narrow or occludable angle (strong anatomic predisposition).

Etiology

Pupillary block (most common)

  • Anteriorly bowed iris against the lens blocks aqueous flow through the pupil.

Anatomic predisposition

  • Shallow AC, narrow angle, short axial length, thick lens, and hyperopia.
  • Demographic risks: Advanced age, Asian ancestry, and female sex.

Precipitants

  • Pharmacologic pupil dilation or dim light.
  • Medications: Anticholinergics, sympathomimetics, or topiramate (ciliary body swelling).

Secondary causes

  • Plateau iris syndrome, neovascularization, or lens-related issues (phacomorphic/phacolytic).
  • Inflammation or posterior segment tumors.

Red Flags

  • IOP >40 mmHg with corneal edema: Retinal ganglion cell loss progresses within hours.
  • Systemic misdiagnosis: Headache, nausea, and vomiting mistaken for migraine or GI distress.
  • Fellow eye risk: 40–80% lifetime attack risk mandates prophylactic LPI.
  • Vision loss: Ipsilateral amaurotic pupil suggests CRAO complication.

Investigations

Clinical exam

  • Slit-lamp: Note pupil reactivity, AC depth, lens thickness, and corneal clarity.
  • Gonioscopy: Both eyes essential; use topical hyperosmolar agents (glycerin) to clear edema for a better view.
  • IOP: Immediate measurement of both eyes.

Fundus exam

  • Look for optic nerve cupping, CRVO, or spontaneous arterial pulsations.

Imaging

  • B-scan ultrasound or UBM if secondary angle closure is suspected.

Treatment

Immediate topical therapy

  • Beta-blocker: Timolol 0.5% (caution with asthma/COPD).
  • Alpha-2 agonist: Brimonidine 1%.
  • Carbonic anhydrase inhibitor: Dorzolamide 2%.
  • Miotic: Pilocarpine 1%.
  • Steroid: Prednisolone acetate 1% to reduce inflammation and edema.
  • Protocol: 3 rounds of drops separated by 15 minutes.

Systemic therapy

  • Acetazolamide: 500 mg IV or 250–500 mg PO.
  • Osmotic agents: Mannitol 1–2 g/kg IV over 45 minutes if refractory (check renal/cardiac status).

Adjuncts

  • Compression gonioscopy: May mechanically open the angle and break the attack.
  • AC paracentesis: For immediate IOP reduction in severe refractory cases.

Definitive treatment

  • YAG laser peripheral iridotomy (LPI): The definitive treatment for pupillary block.
  • Prophylactic LPI: Required for the fellow eye due to high lifetime risk.
  • Lens extraction: For phacomorphic cases once the eye is quiet.

Clinical Pearl

Acute angle-closure is an emergency often masked by systemic symptoms. Nausea and vomiting can lead to a GI misdiagnosis; always check pupils and IOP in patients with severe headache. Fellow eye LPI is mandatory.

Differential Diagnosis

  • • Inflammatory open-angle glaucoma.
  • • Pigmentary glaucoma (transillumination defects).
  • • Lens-related (phacolytic) glaucoma.
  • • Neovascular glaucoma.

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