What is the diagnostic approach for acute angle closure glaucoma (AACG) in the Emergency Department (ED)?

From the Guidelines

Diagnosing acute angle closure glaucoma in the emergency department requires immediate recognition of characteristic symptoms and specific examination findings, including gonioscopy to assess the anterior chamber angle, as recommended by the most recent guidelines 1. To diagnose acute angle closure glaucoma, patients typically present with severe eye pain, headache, blurry vision, halos around lights, nausea, and vomiting. The affected eye often shows a mid-dilated, non-reactive pupil, conjunctival injection, corneal edema, and significantly elevated intraocular pressure (IOP) above 21 mmHg, often reaching 40-80 mmHg when measured with a tonometer. Visual acuity is usually decreased.

Key Examination Findings

• A shallow anterior chamber can be observed with a slit lamp examination
• The anterior chamber angle can be assessed using gonioscopy if available, as recommended by the primary angle-closure disease preferred practice pattern 1
• Gonioscopic visualization of the angle may be impaired secondary to corneal edema, and topical glycerin may be used to clear the cornea to obtain a better view 1

Immediate Treatment

• Immediate treatment should be initiated with topical beta-blockers (timolol 0.5%), alpha-2 agonists (brimonidine 0.2%), and carbonic anhydrase inhibitors (dorzolamide 2%), along with systemic medications including acetazolamide 500mg IV or PO, followed by 250mg every 6 hours, as recommended by the primary angle closure preferred practice pattern guidelines 1
• Hyperosmotic agents like mannitol 1-2g/kg IV over 45 minutes may be needed for severe cases
• Pilocarpine 2% can be used after IOP begins to decrease

Definitive Treatment

• Prompt ophthalmology consultation is essential as definitive treatment often requires laser peripheral iridotomy, which has a favorable risk-benefit ratio 1
• Early diagnosis is critical as permanent vision loss can occur within hours if treatment is delayed. The most recent guidelines recommend identifying patients who currently have or are at risk of developing PACG or AACC by using gonioscopy, and successfully managing AACC with laser iridotomy, and iridoplasty when indicated 1.

From the FDA Drug Label

For adjunctive treatment of: ... preoperatively in acute angle-closure glaucoma where delay of surgery is desired in order to lower intraocular pressure. The diagnosis of acute angle closure glaucoma is not directly addressed in the provided drug label.

• The label mentions the use of acetazolamide in the treatment of acute angle closure glaucoma, but it does not provide information on how to diagnose the condition. 2

From the Research

Diagnosis of Acute Angle Closure Glaucoma

To diagnose acute angle closure glaucoma in the emergency department, the following steps can be taken:

• A detailed interrogation is essential to exclude other possible confounding disorders that present similarly, especially those originating in the CNS 3
• Basic examination of the eye should include:
  • Assessment of the anterior segment with a bright light
  • Measurement of intraocular pressure
  • A full neurological exam 3
• Angle closure should be excluded in all patients presenting with sudden onset of red eye associated with pupillary dilation, dull pain and headache 3
• A step-by-step flow chart for diagnosis of acute angle-closure glaucoma can be used, with explanation of various signs and descriptions of appropriate diagnostic tests 4

Clinical Presentation

The clinical presentation of acute angle closure glaucoma includes:

• Sudden onset of red eye
• Pupillary dilation
• Dull pain
• Headache 3, 5
• Loss of visual acuity 6

Treatment

Immediate treatment must be initiated whenever there is high clinical suspicion of acute angle closure, with the administration of systemic ocular hypotensive therapy to prevent damage to the optic nerve and limit visual loss 3

• Treatment options include:
  • Pilocarpine eye drops
  • Intravenous acetazolamide
  • Bilateral YAG laser iridotomies 6
  • Medical therapy and laser peripheral iridotomy 7
  • Cataract extraction may be more effective at controlling the IOP than laser or incisional glaucoma procedures 7