What are the treatment options for acute angle-closure glaucoma (AACG) causing vision loss?

Treatment of Acute Angle-Closure Glaucoma Causing Vision Loss

Immediately initiate medical therapy to lower intraocular pressure, followed by laser peripheral iridotomy as soon as feasible—this is the definitive treatment to prevent permanent vision loss and optic nerve damage. 1

Immediate Medical Management

The first priority is rapid IOP reduction to relieve symptoms and prevent irreversible optic nerve damage. Start combination medical therapy immediately: 1

• Topical beta-adrenergic antagonists (e.g., timolol) to suppress aqueous production 1
• Topical alpha2-adrenergic agonists (e.g., brimonidine) to reduce aqueous formation 1
• Carbonic anhydrase inhibitors (topical, oral, or IV acetazolamide) to suppress aqueous production 1, 2
• Topical parasympathomimetics (pilocarpine) to constrict the pupil and open the angle 1, 2
• Systemic hyperosmotic agents (oral glycerol or IV mannitol) for rapid IOP reduction 1, 2

Critical Medication Caveats

Important limitations exist with initial medical therapy: 1

• Beta-blockers and carbonic anhydrase inhibitors may be ineffective initially if the ciliary body is ischemic from extremely high IOP 1
• Miotics frequently fail when IOP is markedly elevated due to pressure-induced ischemia of the pupillary sphincter 1
• In secondary pupillary block from intraocular gas, oil, vitreous, or lens malposition, miotics are ineffective and mydriatics may be more effective 1

Definitive Surgical Treatment

Laser Peripheral Iridotomy (First-Line)

Perform laser peripheral iridotomy as soon as possible after medical IOP reduction—this is the preferred definitive treatment with the most favorable risk-benefit ratio. 1

The iridotomy bypasses pupillary block by eliminating the pressure gradient between posterior and anterior chambers, and timely treatment prevents permanent damage to the optic nerve, trabecular meshwork, iris, lens, and cornea. 1

If corneal edema prevents visualization for laser iridotomy: 1

• Apply topical hyperosmotic agents to clear the cornea 1
• Perform anterior chamber paracentesis to rapidly lower IOP 1
• Consider peripheral laser iridoplasty 1

Alternative Surgical Options

When laser iridotomy is not possible or the acute attack cannot be medically broken: 1

• Surgical (incisional) iridectomy remains effective even with cloudy cornea 1
• Anterior chamber paracentesis for immediate IOP reduction 1
• Primary filtering surgery (trabeculectomy) should be considered if extensive synechial closure is present or concurrent glaucomatous optic disc cupping indicates prolonged chronic disease 1
• Primary phacoemulsification (cataract extraction) is effective for maintaining IOP control and reducing medication requirements 1
• Cyclophotocoagulation for cases unresponsive to conventional treatment 1

Critical warning: Filtering surgery in eyes with unbroken acute angle closure carries high risk of anterior chamber shallowing, aqueous misdirection, choroidal effusions, or aqueous hyposecretion postoperatively. 1

Fellow Eye Management

The fellow eye requires urgent prophylactic laser peripheral iridotomy because approximately 50% will develop acute angle closure within 5 years if left untreated. 1

• Schedule prophylactic LPI as soon as possible—attacks can occur within days 1
• Chronic parasympathomimetic (miotic) therapy is not an appropriate alternative; 40% of fellow eyes treated with miotics still develop acute attacks within 5 years 1

Long-Term Management After Iridotomy

Additional IOP-lowering treatment is often necessary even after successful iridotomy: 1

• Trabecular damage or peripheral anterior synechiae formation during the acute attack may cause persistent IOP elevation 1
• Manage persistent elevated IOP similarly to primary open-angle glaucoma with chronic topical ocular hypotensive agents 1
• Goniosynechialysis (surgical lysis of synechiae) or laser iridoplasty may improve aqueous outflow if performed within 6-12 months of the acute attack 1
• Cataract extraction alone leads to substantial IOP lowering in many patients and should be considered as a treatment option 1
• Incisional glaucoma surgery (trabeculectomy or tube shunt) for refractory cases 1

Prognosis and Vision Loss Prevention

Untreated acute angle-closure glaucoma causes rapid and irreversible vision loss. 1

• Glaucomatous optic neuropathy develops rapidly with high IOP 1
• Retinal nerve fiber layer swelling occurs in the first few days, followed by axonal atrophy at 3 months 1
• In long-term follow-up (4-10 years), 18% of eyes become blind (50% from glaucoma), and 58% have visual acuity worse than 20/40 1
• This creates significant visual morbidity with progressive vision loss that may result in bilateral blindness 1

The key to preventing permanent vision loss is immediate medical therapy followed by definitive laser iridotomy performed as soon as feasible, with prophylactic treatment of the fellow eye. 1, 2