Angle-Closure vs Open-Angle Glaucoma: Clinical Presentation
Angle-closure glaucoma presents as an ophthalmologic emergency with severe eye pain, headache, blurred vision, a mid-dilated rigid pupil, and conjunctival redness, while open-angle glaucoma is typically asymptomatic and discovered incidentally through elevated intraocular pressure (IOP >21 mmHg), suspicious optic disc changes, or visual field defects detected during routine examination. 1
Acute Angle-Closure Glaucoma Presentation
Emergency Features:
- Severe ocular pain and/or headache with acute onset 2
- Nausea and vomiting accompanying the eye symptoms 2
- Blurred vision with rapid deterioration 2, 1
- Mid-dilated, fixed pupil that does not react to light 2
- Conjunctival hyperemia (red eye) 2
- Corneal edema from elevated pressure 3
Mechanism:
- Obstruction of aqueous humor outflow due to narrow or closed anterior chamber angle 1
- Often triggered by pupillary dilation in susceptible individuals 1
- Requires immediate IOP reduction to prevent permanent optic nerve damage 3
Primary Open-Angle Glaucoma Presentation
Insidious Onset:
- Completely asymptomatic in early to moderate stages 1
- Up to 50% of patients are undiagnosed because the disease progresses silently over years 1
- Patients maintain normal vision until advanced stages 4
Diagnostic Findings (Not Symptoms):
- Elevated IOP >21 mmHg on tonometry, though can occur with normal pressures 4
- Cup-to-disc ratio ≥0.3 or progressive cupping 1
- Retinal nerve fiber layer defects on optical coherence tomography 1
- Reproducible visual field defects in characteristic glaucomatous patterns 4
- Open anterior chamber angle on gonioscopy (key distinguishing feature) 4
Key Distinguishing Features
| Feature | Angle-Closure | Open-Angle |
|---|---|---|
| Onset | Acute, hours [2] | Chronic, years [1] |
| Pain | Severe [2] | None [1] |
| Vision Loss | Rapid [3] | Gradual [1] |
| Anterior Chamber | Shallow, closed angle [3] | Open angle [4] |
| IOP | Very high (>40 mmHg) [3] | Elevated or normal [4] |
| Pupil | Mid-dilated, fixed [2] | Normal [1] |
Treatment Differences
Acute Angle-Closure (Emergency):
- Immediate medical IOP reduction with topical beta-blockers, carbonic anhydrase inhibitors, alpha-2 agonists 2
- Systemic carbonic anhydrase inhibitors (acetazolamide) 5, 2
- Osmotic agents (mannitol) for rapid pressure reduction 2
- Laser peripheral iridotomy as definitive treatment to prevent recurrence 3
- Treat fellow eye prophylactically with laser iridotomy 3
Primary Open-Angle (Chronic Management):
- Topical IOP-lowering medications as first-line (prostaglandin analogs, beta-blockers, carbonic anhydrase inhibitors, alpha-2 agonists) 1
- Selective laser trabeculoplasty as alternative first-line option 1
- Target 20% IOP reduction in glaucoma suspects based on OHTS data 4
- Monitoring every 12-24 months for suspects, more frequently if high-risk 4
- Trabeculectomy or tube shunt if medical/laser therapy fails 6
Critical Clinical Pitfall
Do not confuse chronic angle-closure with open-angle glaucoma. Both can present with gradual vision loss and elevated IOP, but gonioscopy reveals the closed angle in chronic angle-closure, requiring different surgical management (lens extraction, iridotomy, or goniosynechialysis) rather than standard trabeculectomy alone 6, 7, 3. Always perform gonioscopy when evaluating any glaucoma patient 4.