Case studies · Ophthalmology · 7 November 2026

Acute angle‑closure glaucoma case study

The case

Patient: 58‑year‑old female, teacher

Presenting complaint: Sudden, severe pain in the right eye for 6 hours, associated with blurred vision, halos around lights, nausea and one episode of vomiting.

History of present illness:

• The pain began abruptly while she was reading.
• She describes the pain as “sharp, throbbing” and rated it 9/10.
• Vision in the right eye became hazy within minutes; she sees colored halos around street lamps.
• She reports a headache and a feeling of fullness in the right ear.
• No prior ocular trauma or surgery.

Past ocular history:

• Presbyopia, uses reading glasses.
• No known glaucoma, cataract, or retinal disease.

Systemic history:

• Hypertension diagnosed 5 years ago, on amlodipine 5 mg daily.
• No diabetes, no coronary artery disease.

Medications: Amlodipine 5 mg daily, occasional over‑the‑counter antihistamine for seasonal allergies.

Family history: Mother had cataract surgery at 70 years; no known glaucoma.

Social history: Non‑smoker, occasional wine, works as a school teacher, lives in a city with moderate altitude.

Examination:

Vital signs:

• Blood pressure: 138/84 mm Hg
• Pulse: 88 bpm, regular
• Respiratory rate: 16 /min
• Temperature: 36.8 °C

Initial investigations (performed after initial IOP‑lowering therapy):

• IOP (re‑measured after 1 hour of topical therapy): OD 38 mm Hg, OS 16 mm Hg
• Anterior segment OCT (right eye): Anterior chamber depth 1.8 mm, angle opening distance at 500 µm (AOD500) 0.15 mm (normal ≥0.25 mm)
• B‑scan ultrasonography: No posterior segment pathology, normal axial length (23.5 mm)
• Serum electrolytes: Na 140 mmol/L, K 4.2 mmol/L, Cl 102 mmol/L (within normal limits) – done to rule out systemic cause of secondary IOP rise.

The patient was started emergently with:

• Topical timolol 0.5 % BID, dorzolamide 2 % TID, apraclonidine 1 % QID
• Oral acetazolamide 500 mg loading dose, then 250 mg q6h
• Intravenous mannitol 1 g/kg over 45 min (total 70 g)

After 2 hours, the pain decreased, and IOP fell to 28 mm Hg.

Questions

1. What is the most likely diagnosis?
2. Which clinical findings in the history and examination point toward this diagnosis, and why?
3. List the investigations that confirm the diagnosis and explain the significance of their results.
4. Outline the acute management steps for this patient, including pharmacologic and laser/surgical options, with current guideline references.
5. Discuss the possible short‑term and long‑term complications if the condition is not promptly treated.

Answers

1. Diagnosis

The most likely diagnosis is Acute Primary Angle‑Closure Glaucoma (APACG) affecting the right eye.

• The presentation is classic: sudden, severe ocular pain, blurred vision with halos, nausea/vomiting, mid‑dilated non‑reactive pupil, conjunctival injection, corneal edema, and markedly elevated IOP (>30 mm Hg).
• The patient has risk factors for angle closure: age >50 years, female sex, hyperopic tendency (shallow anterior chamber), and possible pupillary dilation from antihistamine use.

2. Clinical findings that point toward APACG

3. Investigations and their significance

1. Goldmann Applanation Tonometry – Gold standard for IOP measurement. An IOP >30 mm Hg in the acute setting is diagnostic; the measured 52 mm Hg confirms severe elevation.

2. Gonioscopy – Direct assessment of the angle. Closed angle (0–10°) in all quadrants confirms that the mechanism is appositional closure of the trabecular meshwork.

3. Anterior Segment OCT (AS‑OCT) – Non‑contact imaging of the angle. AOD500 of 0.15 mm (normal ≥0.25 mm) quantifies the narrow angle and supports the diagnosis.

4. Slit‑lamp examination – Shows corneal edema, shallow chamber, and pupil changes; essential for bedside diagnosis.

5. Fundoscopy – May reveal optic disc swelling; helps to assess for glaucomatous damage and rule out other posterior segment pathology.

6. B‑scan ultrasonography – Used when media opacity prevents fundus view; confirms normal posterior segment, excluding secondary causes like choroidal effusion.

7. Systemic labs (electrolytes, renal function) – Baseline before acetazolamide or mannitol; ensures safe administration of carbonic anhydrase inhibitors and osmotic agents.

All these investigations together confirm primary acute angle‑closure glaucoma by demonstrating a narrow angle, elevated IOP, and characteristic anterior segment changes.

4. Acute management

Management aims to lower IOP rapidly, break the pupillary block, and then prevent recurrence. The American Academy of Ophthalmology (AAO) Preferred Practice Pattern (PPP) for Primary Angle‑Closure Glaucoma, 2023, outlines the following steps:

4.1 Immediate IOP‑lowering (first 1–2 hours)

Key point: Pilocarpine is ineffective while IOP >40 mm Hg because the sphincter muscle is ischemic; therefore, it is given after initial IOP reduction.

4.2 Definitive angle‑opening procedure (within 24 h)

1. Laser peripheral iridotomy (LPI) – First‑line definitive treatment.

   • Procedure: Nd:YAG laser (or combined argon‑Nd:YAG) creates a 0.5–1 mm full‑thickness opening in the peripheral iris, allowing aqueous to bypass the pupillary block.
   • Timing: After IOP ≤30 mm Hg and corneal edema cleared enough for visualization (usually within 12–24 h).
   • Success rate: >90 % in preventing recurrence.

2. If LPI fails or is contraindicated – Consider laser iridoplasty (peripheral iris bombe reduction) or surgical iridectomy (manual removal of a peripheral iris segment).

4.3 Post‑acute phase (preventive)

• Laser peripheral iridotomy in the fellow eye (prophylactic) – 80–90 % of fellow eyes have narrow angles.
• Topical IOP‑lowering agents (e.g., prostaglandin analogues) may be continued for a few weeks until the angle stabilizes.
• Patient education – Avoid pupillary dilating agents, maintain hydration, and seek immediate care if symptoms recur.

4.4 Follow‑up schedule (AAO 2023)

• Day 1–2: Re‑measure IOP, assess corneal clarity, confirm patency of LPI.
• Week 1: Gonioscopy to document angle status, optic disc evaluation.
• Month 1 and 3: Visual field testing (Humphrey 24‑2) to detect early functional loss.

5. Complications of delayed or inadequate treatment

Prompt IOP reduction and definitive iridotomy dramatically reduce the risk of these complications.

Key learning points

• Acute primary angle‑closure glaucoma presents with a classic triad: severe ocular pain, blurred vision with halos, and nausea/vomiting.
• Mid‑dilated, poorly reactive pupil and corneal edema are bedside clues that the IOP is markedly elevated.
• IOP >30 mm Hg measured by Goldmann applanation tonometry is diagnostic; values >50 mm Hg indicate a true emergency.
• Gonioscopy is essential to demonstrate a closed angle; AS‑OCT can quantify angle width when gonioscopy is difficult.
• Initial management follows a stepwise pharmacologic regimen: topical β‑blocker, α2‑agonist, carbonic anhydrase inhibitor, systemic acetazolamide, and IV mannitol, followed by pilocarpine after IOP falls below 40 mm Hg.
• Laser peripheral iridotomy performed within 24 h is the definitive treatment; prophylactic LPI of the fellow eye is recommended.
• Untreated attacks can cause irreversible optic neuropathy, corneal decompensation, PAS formation, and secondary cataract.
• Follow‑up includes IOP monitoring, gonioscopy, optic disc assessment, and visual field testing per AAO PPP 2023.

Practice MCQs

1. Which of the following is the most appropriate first‑line pharmacologic agent to be given after the IOP has been lowered to <40 mm Hg in an acute angle‑closure attack?
A. Timolol 0.5 % eye drops
B. Pilocarpine 2 % eye drops
C. Brimonidine 0.15 % eye drops
D. Dorzolamide 2 % eye drops

Answer: B — Pilocarpine is a miotic that contracts the sphincter pupillae, pulling the peripheral iris away from the trabecular meshwork and breaking the pupillary block. It is ineffective when IOP is >40 mm Hg because the iris sphincter is ischemic; therefore it is administered after initial IOP reduction.

2. A 62‑year‑old man presents with an acute painful red eye. His IOP is 55 mm Hg, and gonioscopy shows a closed angle. Which laser procedure provides the definitive treatment for this condition?
A. Argon laser trabeculoplasty
B. Nd:YAG laser peripheral iridotomy
C. Selective laser trabeculoplasty
D. Laser cyclophotocoagulation

Answer: B — Nd:YAG laser peripheral iridotomy creates a full‑thickness opening in the peripheral iris, allowing aqueous to bypass the pupillary block and permanently opening the angle. This is the standard definitive treatment for acute primary angle‑closure glaucoma.

3. Which of the following complications is most directly related to prolonged corneal edema during an untreated acute angle‑closure attack?
A. Peripheral anterior synechiae
B. Bullous keratopathy
C. Neovascular glaucoma
D. Retinal detachment

Answer: B — Persistent corneal edema damages the endothelial cell layer, leading to loss of pump function and development of bullous keratopathy. While PAS can also result from prolonged high IOP, the direct sequela of corneal edema is endothelial decompensation.

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