Glaucoma
Acute Angle Closure Glaucoma
Also known as: AACG, acute angle closure, acute glaucoma, acute congestive glaucoma, primary angle closure glaucoma acute, angle closure attack, acute IOP spike, sudden severe eye pain
Filed as: Emergency
Source-cited from the record's own evidence list. Clinical content programme led by Dr Ankit Mathur, PhD, Grad Cert Ocu Thera, B.S. Optom. How the clinical content is governed
Clinical decision support only
Overview
A sight-threatening emergency caused by sudden blockage of aqueous humour outflow at the trabecular meshwork by the peripheral iris. Leads to acute, severe elevation of intraocular pressure (typically > 40 mmHg). Immediate emergency ophthalmology/ED referral is required; IOP-lowering support may be needed while urgent transfer is being arranged within local scope and protocol. The fellow eye is at high risk.
Recognition
Symptoms: what patients report
- Sudden, severe, unilateral eye pain — aching or throbbing, often severe.
- Headache, nausea, and vomiting — systemic symptoms can lead to misdiagnosis as migraine or GI illness.
- Blurred or markedly reduced vision.
- Coloured haloes around lights (corneal oedema causing light diffraction).
- Red eye.
- Symptoms may be precipitated by: dim lighting (pupil dilation), reading (increased relative pupil block), topical mydriatics, systemic anticholinergic drugs.
Signs: what the examination shows
- Fixed mid-dilated pupil (approximately 4–6mm) — oval, non-reactive or poorly reactive.
- Corneal oedema — steamy, hazy, dull corneal reflex (epithelial oedema from elevated IOP).
- Ciliary flush — limbal injection surrounding the cornea.
- Elevated IOP — often > 40 mmHg, sometimes > 60 mmHg; eye feels hard on palpation.
- Shallow anterior chamber — visible on slit lamp as narrow or flat AC.
- Glaukomflecken — grey-white anterior lens opacities that are highly suggestive of prior acute angle closure.
- Fundus: disc oedema or venous congestion in severe prolonged attacks.
- Fellow eye: narrow anterior chamber angles on gonioscopy.
What OptoGuide™ covers for acute angle closure glaucoma
- Pattern reasoning: what this combination of findings points to, and its differentiators
- Don't-miss risks and escalation triggers
- Management tiers with linked Australian therapeutics
- Referral urgency, specialty, and letter drafting
Sources
- Primary angle closure / PAC / PACG — College of Optometrists CMG
- Primary Angle-Closure Disease Preferred Practice Pattern®. Gedde SJ, Chopra V, Vinod K, et al. Ophthalmology. 2026;133(4):P153-P201.
- Treatment of pseudophakic aqueous misdirection syndrome. Lincke JB, Häner N, Schawkat M, Zinkernagel MS, Unterlauft JD. Scientific Reports. 2025;15(1):1415.
- Posner-Schlossman Syndrome. Megaw R, Agarwal PK. Survey of Ophthalmology. 2017 May - Jun;62(3):277-285.
Standard texts: Kanski's Clinical Ophthalmology: A Systematic Approach, The Wills Eye Manual, Oxford Handbook of Ophthalmology, Oxford American Handbook of Ophthalmology, Signs in Ophthalmology: Causes & Differential Diagnosis.