Acute angle-closure glaucoma occurs when the iris bulges forward and seals off the trabecular meshwork from the anterior chamber preventing aqueous humour from being able to drain away, leading to a continual buildup of IOP
Aetiology
Risk factors
Hyperopia (long-sightedness) and short axial length of the eyeball
Age - the lens grows with age and can push the iris forwards into the angle
Ethnicity - Asian or Inuit populations
Pupillary dilatation - either iatrogenically (eg. topical mydriatics or systemic alpha-adrenergic agonists) or owing to the patient being in a dimly lit environment (eg. watching television in a dark room)
Pathophysiology
In health, aqueous humour, which is produced by the ciliary body, flows through the pupil and leaves the eye via the trabecular meshwork
The trabecular meshwork is a circular structure that lies in the anterior chamber angle, which is where the cornea meets the iris
Primary angle-closure glaucoma occurs when the iris blocks the drainage angle, which causes a rise in IOP and subsequent damage to the optic nerve
Primary angle closure is the term used to describe when the iris blocks the drainage angle but there is no evidence of optic nerve damage
Clinical features
Symptoms
Pain: an extremely painful eye that develops rapidly, with pain spreading throughout the orbit
Blurred vision: can progress to vision loss
Systemically unwell: nausea and vomiting are very common presenting symptoms
Haloes: patients will often describe coloured haloes around lights