Acute closed‑angle glaucoma
Acute closed‑angle glaucoma (AACG) is an ophthalmic emergency in which the iridocorneal angle becomes occluded, abruptly preventing aqueous humour outflow and causing a rapid rise in intraocular pressure (IOP). Rapid recognition and temporary medical treatment in the emergency department (ED), followed by urgent ophthalmology review for definitive therapy, are essential to preserve vision.
Pathophysiology
- Aqueous humour normally flows from the posterior chamber through the pupil into the anterior chamber and drains via the trabecular meshwork at the iridocorneal angle.
- In AACG the peripheral iris bows forward (commonly from pupillary‑block but other mechanisms occur), mechanically obstructing the trabecular meshwork and producing a precipitous rise in IOP.
- Elevated IOP causes corneal oedema, iris ischaemia and optic nerve dysfunction, producing a rapid risk of permanent visual loss.
- The fellow eye is often anatomically predisposed to angle closure.
Epidemiology and risk factors
- Typical age is the sixth to seventh decades.
- Risk is higher in hyperopic eyes with a shallow anterior chamber, in females, and in people of Asian ethnicity.
- Anatomical risks include shallow anterior chamber and narrow iridocorneal angle.
- A positive family history increases susceptibility.
Clinical presentation
Onset is usually sudden and severe. Typical features include: