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Acute Angle-Closure Glaucoma — IOP-Lowering Sequence and Laser Iridotomy

System: Ophthalmology • Reviewed: Sep 1, 2025 • Step 1Step 2Step 3

Synopsis:

Painful red eye with halos, mid-dilated pupil, corneal edema, and high IOP. Lower pressure with sequential topical and systemic therapy and arrange urgent laser peripheral iridotomy in both eyes when appropriate.

Key Points

  • Use the highest‑yield diagnostic test early; do not let testing delay time‑critical therapy.
  • Set objective targets (hemodynamic, neurologic, respiratory) and reassess frequently.
  • Plan definitive source control or reperfusion when indicated; document follow‑up and patient education.

Algorithm

  1. Diagnose clinically; check IOP and vision.
  2. Initial drops: timolol + α2-agonist; give acetazolamide 500 mg IV/PO.
  3. Add pilocarpine once IOP begins to fall; repeat topical agents per protocol.
  4. If inadequate, give IV mannitol; antiemetics/analgesia.
  5. Urgent ophthalmology for laser peripheral iridotomy; treat fellow eye prophylactically when indicated.

Clinical Synopsis & Reasoning

Painful red eye with halos, mid-dilated pupil, corneal edema, and high IOP. Lower pressure with sequential topical and systemic therapy and arrange urgent laser peripheral iridotomy in both eyes when appropriate.


Treatment Strategy & Disposition

Stabilize ABCs. Initiate guideline‑concordant first‑line therapy with precise dosing and continuous monitoring. Escalate to advanced or procedural interventions based on explicit failure criteria. Define ICU, step‑down, and ward disposition triggers; involve specialty teams early.


Epidemiology / Risk Factors

  • Risk varies by comorbidity and precipitants; see citations for condition‑specific data.

Investigations

TestRole / RationaleTypical FindingsNotes
Tonometry (IOP)Diagnosis/severityMarkedly elevatedTrack response
Gonioscopy (if available)Angle statusClosed/narrow angleSpecialist skill
Slit lamp examCornea/anterior chamberEdema, shallow chamber

Pharmacology

Medication/InterventionMechanismOnsetRole in TherapyLimitations
Timolol 0.5% 1 dropβ-blocker (topical)Minutes↓ Aqueous productionContraindicated in asthma/heart block
Apraclonidine/Brimonidine 1 dropα2-agonist (topical)Minutes↓ Aqueous productionDry mouth, fatigue
Pilocarpine 1–2% 1 drop (after IOP starts to fall)MioticMinutes-hoursOpens angle via pupillary constrictionIneffective when IOP very high initially
Acetazolamide 500 mg IV/POCarbonic anhydrase inhibitorHours↓ Aqueous productionAvoid in sulfa allergy; renal dosing
Mannitol 1–2 g/kg IVOsmotic diureticHoursRapid IOP reduction if refractoryMonitor volume/osmolality

Prognosis / Complications

  • Outcome depends on timeliness of diagnosis and definitive therapy; monitor for complications.

Patient Education / Counseling

  • Provide red‑flag education, adherence guidance, and explicit return precautions; arrange timely specialty follow‑up.

References

  1. AAO Preferred Practice Pattern: Primary Angle Closure (2020) — Link

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