angleclosure

Angle-closure is a condition in which the iridocorneal angle is closed or narrowed, hindering drainage of aqueous humor through the trabecular meshwork and causing elevated intraocular pressure (IOP). It can be primary or secondary and may present as an acute angle-closure crisis or as chronic angle-closure with progressive angle narrowing and optic nerve injury.

Pathophysiology and risk factors

Most cases arise from pupillary block or anterior segment crowding, including lens enlargement, plateau iris configuration, or thick iris tissue, which narrows or closes the angle. Risk factors include older age, female sex, shallow anterior chamber, hyperopia, and certain ethnic backgrounds, particularly East Asian populations. Chronic contact between the iris and the trabecular meshwork can cause peripheral anterior synechiae and permanent angle closure.

Clinical features and diagnosis

Acute angle closure presents with sudden eye pain, headache, nausea, vomiting, blurred vision, halos around lights, and a mid-dilated pupil; exam often shows corneal edema and conjunctival injection. Chronic angle closure may be less symptomatic until glaucomatous damage develops. Diagnosis relies on gonioscopy to identify occludable angles; prior imaging with ultrasound biomicroscopy (UBM) or anterior segment optical coherence tomography (AS-OCT) helps define the mechanism. IOP is typically elevated during attacks.

Management

Acute management aims to rapidly lower IOP with topical medications (beta-blockers, alpha agonists), systemic acetazolamide, and hyperosmotic agents as needed, plus analgesia and antiemetics. Once IOP is controlled, definitive treatment to relieve pupillary block is laser peripheral iridotomy (LPI) or surgical iridectomy; lens extraction may be considered when lens-induced crowding contributes. In chronic angle-closure with synechial obstruction, glaucoma procedures or lens removal may be required.

Prognosis and prevention

Preventive treatment in at-risk eyes, such as performing LPI, reduces recurrence risk. Outcomes depend on prompt treatment; delayed intervention increases the risk of irreversible optic nerve damage and vision loss.