Acute angle-closure glaucoma is an ophthalmologic emergency characterized by abrupt obstruction of aqueous outflow due to appositional closure of the anterior chamber angle, causing a rapid rise in intraocular pressure (IOP) that can lead to irreversible blindness within hours if not promptly treated. [1-2]
1. History
- Onset and timing: Sudden onset of severe unilateral eye pain, often in the evening or in dim lighting (pupillary dilation triggers closure) [3]
- Vision changes: Acute blurred vision, halos around lights; ask about prior intermittent episodes of halos/blurring that resolved spontaneously (prodromal subacute attacks) [3-4]
- Associated symptoms: Ipsilateral headache (often frontal/periorbital), nausea, vomiting — can mimic migraine or intracranial pathology [4-5]
- Precipitants: Recent activity in dim lighting, pharmacologic mydriasis, recent medication changes (topiramate, anticholinergics, adrenergics, SSRIs, sulfonamides, inhaled ipratropium/salbutamol) [4][6]
- Important negatives: No trauma, no discharge/crusting, no floaters or flashes (helps distinguish from retinal detachment), no temporal artery tenderness
2. Alarm Features
- IOP >40 mmHg with a fixed, mid-dilated pupil — indicates ischemic sphincter paralysis [4-5]
- Severe vision loss at presentation — suggests optic nerve damage already occurring
- Bilateral involvement (rare but possible)
- Nausea/vomiting severe enough to mimic an acute abdomen or intracranial emergency — risk of misdiagnosis and delayed treatment [2]
- Up to 50% of patients with AACC subsequently develop angle-closure glaucoma [2]
3. Medications
Precipitating medications (high-yield for ED)
- Anticholinergics (atropine, scopolamine, oxybutynin, antihistamines)
- Adrenergics (phenylephrine, ephedrine, inhaled sympathomimetics)
- Topiramate and sulfonamides — cause ciliary body edema and forward lens shift (non-pupillary block mechanism) [3][6]
- SSRIs/SNRIs, tricyclic antidepressants — mild anticholinergic/adrenergic effects [7]
- Inhaled ipratropium bromide [4]
Acute treatment medications (see Treatment Plan below)
Contraindications/cautions
- Pilocarpine is ineffective at IOP >40 mmHg due to ischemic iris sphincter paralysis — lower IOP first with aqueous suppressants [3-4]
- Do NOT use pilocarpine if topiramate-induced angle closure (non-pupillary block mechanism; cycloplegics/mydriatics are preferred instead) [3]
- Timolol: avoid in asthma/COPD, bradycardia, heart block
- Acetazolamide: avoid in sulfa allergy (relative), severe renal failure, hypokalemia
- Mannitol: caution in CHF, renal failure
4. Diet
- Not a primary factor in acute angle-closure glaucoma
- Hydration: Avoid large-volume fluid boluses in patients with known narrow angles (rapid fluid intake can transiently raise IOP)
- NPO if surgical intervention (anterior chamber paracentesis, iridotomy) is anticipated
5. Review of Systems
- Eyes: Pain, redness, blurred vision, halos, photophobia, tearing
- Neuro: Headache (frontal/periorbital), nausea, vomiting — critical to distinguish from migraine, subarachnoid hemorrhage, or stroke
- GI: Nausea/vomiting (can be the dominant complaint, leading to misdiagnosis)
- Cardiac: Chest pain, palpitations (relevant for medication safety — β-blockers)
- Pulmonary: Asthma/COPD history (timolol contraindication)
6. Collateral History and Family History
- Family history of angle closure is a recognized risk factor [2][4]
- Prior episodes of intermittent blurred vision or halos (subacute attacks)
- History of eye surgery, prior laser iridotomy, or known narrow angles
- Medication list from family/pharmacy — especially recent additions of anticholinergics, topiramate, or antidepressants [4]
7. Risk Factors
- Asian descent (particularly East Asian) — highest prevalence [4][6]
- Female sex (2–4× more common than males) [2][4]
- Older age (typically >40 years, peak 55–70) [4]
- Hyperopia (farsightedness — shorter axial length, shallower anterior chamber) [3-4]
- Short axial length and thick, anteriorly positioned crystalline lens [4]
- Advanced cataracts (lens thickening narrows the angle) [6-7]
- Low body weight [7]
- Medications with anticholinergic, adrenergic, or sulfonamide properties [3-4]
8. Differential Diagnosis
- Acute iritis/anterior uveitis — painful red eye, but pupil is typically miotic (not mid-dilated), IOP usually normal or low, cells/flare on slit lamp
- Corneal abrasion/keratitis — pain, tearing, photophobia; fluorescein uptake positive; IOP normal
- Conjunctivitis — diffuse injection, discharge; no IOP elevation, no vision loss
- Migraine — unilateral headache with nausea/vomiting but no IOP elevation, no corneal edema, normal pupil
- Retrobulbar hemorrhage — proptosis, restricted extraocular movements, elevated IOP; usually post-traumatic
- Neovascular glaucoma — elevated IOP with rubeosis iridis; associated with diabetic retinopathy, CRVO
- Phacomorphic glaucoma — intumescent cataract pushing iris forward; similar presentation
- Subarachnoid hemorrhage/intracranial pathology — headache, nausea, vomiting; no eye findings on exam (critical not to miss)
9. Past Medical History
- Prior episodes of eye pain, halos, or transient blurred vision (subacute angle closure)
- Known narrow angles or prior gonioscopy findings
- Previous laser iridotomy or cataract surgery
- Hyperopia/refractive error history
- History of cataracts
- Systemic conditions: diabetes, hypertension (relevant for medication choices and neovascular glaucoma risk)
10. Physical Exam
Vital signs: Hypertension and tachycardia may be present secondary to pain; bradycardia possible from vagal response to nausea/vomiting
Eye exam findings
- Conjunctival/ciliary injection (circumcorneal flush) [4-5]
- Corneal edema — hazy, "steamy" cornea [4-5]
- Mid-dilated, fixed pupil — nonreactive or poorly reactive to light [4-6]
- Shallow anterior chamber — assessed by oblique flashlight test (penlight from temporal side: nasal iris in shadow indicates shallow chamber) [6]
- Elevated IOP on palpation (rock-hard globe compared to contralateral eye)
- Fellow eye: Often has a narrow angle — examine for comparison [5]
Signs of prior attacks: Glaukomflecken (anterior subcapsular lens opacities), iris atrophy, posterior synechiae [5]
11. Lab Studies
- No specific labs are diagnostic for AACG
- Pre-treatment labs if using IV mannitol: BMP (renal function, potassium), glucose
- CBC if systemic illness is in the differential
- Acetazolamide can cause metabolic acidosis and hypokalemia — monitor electrolytes if prolonged use anticipated
12. Imaging
- No imaging is required for diagnosis in the ED — this is a clinical and tonometric diagnosis
- Slit-lamp examination is the key diagnostic tool (corneal edema, shallow anterior chamber, flare)
- Gonioscopy (by ophthalmology): gold standard for confirming angle closure — reveals ≥180° iridotrabecular contact [4]
- Anterior segment OCT or ultrasound biomicroscopy (UBM): Can aid in diagnosis; UBM uniquely identifies plateau iris [4]
- CT/MRI head: Only if intracranial pathology (SAH, stroke) is being considered in the differential
13. Special Tests
- Tonometry (Goldmann applanation or Tono-Pen): IOP typically 50–80 mmHg (normal 10–21 mmHg) [4-6]
- Oblique flashlight test: Bedside screening for shallow anterior chamber — shadow on nasal iris when light shone from temporal side [6]
- Gonioscopy: Definitive angle assessment (performed by ophthalmology) [4]
- Van Herick technique: Slit-lamp estimation of anterior chamber depth at the peripheral cornea
14. ECG
- Not routinely indicated for AACG itself
- Obtain ECG if:
- Planning to use topical timolol in patients with cardiac history (can cause bradycardia, heart block)
- Bradycardia from vagal response to severe pain/nausea
- Elderly patient with chest pain or syncope in the differential
15. Assessment
Acute angle-closure crisis is defined by an occluded angle with symptomatic, markedly elevated IOP. [4] The classic triad is a painful red eye, mid-dilated fixed pupil, and hazy cornea. [5][9] Nausea and vomiting can dominate the presentation, leading to misdiagnosis as migraine, gastroenteritis, or even acute abdomen. Severity correlates with the degree and duration of IOP elevation — prolonged attacks cause irreversible damage to the optic nerve, trabecular meshwork, corneal endothelium, and iris. [2] Iridotomy successfully aborts the attack in 42–72% of cases, and many patients recover without permanent visual field damage if IOP is promptly controlled. [9]
16. Treatment Plan
Initial stabilization (ED)
- Topical timolol 0.5% — 1 drop to affected eye [3]
- Topical apraclonidine 1% (or brimonidine 0.2%) — 1 drop [3]
- IV acetazolamide 500 mg — immediate aqueous suppression [3]
- Topical pilocarpine 1–2% — 1 drop q15min × 2 doses, but only after IOP is reduced below 40 mmHg (iris sphincter is ischemic at higher pressures) [3-4][8]
- IV mannitol 20% (1–2 g/kg) — if IOP remains refractory to above measures [3]
- Antiemetics (ondansetron) and analgesics for comfort [1]
- Position patient supine — may help lens fall posteriorly and open the angle
Definitive treatment (ophthalmology)
- Laser peripheral iridotomy (LPI) — preferred definitive treatment once IOP is lowered and cornea clears [1][4][9]
- Anterior chamber paracentesis — if medical therapy fails; performed by ophthalmology only [1]
- Lens extraction (phacoemulsification) — alternative to LPI, especially if visually significant cataract is present; the EAGLE trial showed superior IOP control and quality of life vs. LPI for PAC with elevated IOP and PACG [1][10]
- Prophylactic LPI to the contralateral eye is recommended to prevent second-eye involvement [1][11]
17. Disposition
- Emergent ophthalmology consultation is required for all cases of suspected AACG [1][6]
- Admission criteria:
- IOP not adequately controlled despite maximal medical therapy
- Need for IV mannitol or ongoing IV acetazolamide
- Significant comorbidities complicating management
- Inability to obtain timely ophthalmology follow-up for definitive LPI
- Discharge criteria:
- IOP successfully lowered and attack broken
- Ophthalmology has performed or scheduled LPI within 24–48 hours
- Patient is comfortable, tolerating PO, and has reliable follow-up
- Specialist consultation triggers:
- All cases require ophthalmology — this is not a condition managed independently by the ED or primary care [1]
- Refractory cases may need surgical iridectomy or filtering surgery [4]
18. Follow Up / Return Precautions
- Follow-up with ophthalmology within 24–48 hours for definitive LPI if not performed during the acute visit
- Contralateral eye should be evaluated and treated prophylactically [1][11]
- Return precautions — instruct patients to return immediately for:
- Recurrence of eye pain, redness, or blurred vision
- Halos around lights
- Nausea/vomiting with eye symptoms
- Vision changes in either eye
- Long-term counseling:
- Avoid medications with anticholinergic or adrenergic properties without ophthalmology clearance [4]
- Inform all future providers of the diagnosis (especially before any procedure requiring mydriatic drops)
- Even after successful LPI, periodic follow-up is essential — eyes may still develop elevated IOP over time [9]
- Up to 50% of AACC patients develop chronic angle-closure glaucoma, requiring ongoing monitoring [2]
References
1. Glaucoma in Adults—Screening, Diagnosis, and Management: A Review. — Stein JD, Khawaja AP, Weizer JS. The Journal of the American Medical Association. 2021.
2. Potentially Missed Opportunities in Prevention of Acute Angle-Closure Crisis. — Wu AM, Stein JD, Shah M. JAMA Ophthalmology. 2022.
3. Glaucoma: Diagnosis and Management. — Michels TC, Ivan O. American Family Physician. 2023.
4. Primary Angle-Closure Disease Preferred Practice Pattern®. — Gedde SJ, Chen PP, Muir KW, et al. Ophthalmology. 2021.
5. Lens Extraction Versus Laser Peripheral Iridotomy for Acute Primary Angle Closure. — Ong AY, McCann P, Perera SA, et al. The Cochrane Database of Systematic Reviews. 2023.
6. Sudden Vision Loss: A Diagnostic Approach. — Fraser JA, Son M, Vinokurtseva A. American Family Physician. 2025.
7. Risk Factors for Primary Angle-Closure Glaucoma: A Systematic Review and Meta-Analysis of 45 Studies. — Wang Y, Dong XX, Hou XW, Pan CW. Optometry and Vision Science : Official Publication of the American Academy of Optometry. 2023.
8. FDA Drug Label. — Updated date: 2020-05-19. Food and Drug Administration.
9. The Pathophysiology and Treatment of Glaucoma: A Review. — Weinreb RN, Aung T, Medeiros FA. The Journal of the American Medical Association. 2014.
10. Glaucoma: Now and Beyond. — Jayaram H, Kolko M, Friedman DS, Gazzard G. Lancet. 2023.
11. Glaucoma. — Jonas JB, Aung T, Bourne RR, et al. Lancet. 2017.