Introduction

Glaucoma is a group of disorders characterised by optic neuropathy due, in the majority of patients, to raised intraocular pressure (IOP). It is now recognised that a minority of patients with raised IOP do not have glaucoma and vice versa.

Epidemiology

  • Incidence: 10.00 cases per 100,000 person-years
  • Peak incidence: 70+ years
  • Sex ratio: more common in females 3:1
Condition Relative
incidence
Anterior uveitis4.00
Acute angle closure glaucoma1
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Aetiology

In acute angle-closure glaucoma (AACG) there is a rise in IOP secondary to an impairment of aqueous outflow. Factors predisposing to AACG include:
  • hypermetropia (long-sightedness)
  • pupillary dilatation
  • lens growth associated with age

Clinical features

Features
  • severe pain: may be ocular or headache
  • decreased visual acuity
  • symptoms worse with mydriasis (e.g. watching TV in a dark room)
  • hard, red-eye
  • haloes around lights
  • semi-dilated non-reacting pupil
  • corneal oedema results in dull or hazy cornea
  • systemic upset may be seen, such as nausea and vomiting and even abdominal pain

Management

The management of AACG is an emergency and should prompt urgent referral to an ophthalmologist. Emergency medical treatment is required to lower the IOP with more definitive surgical treatment given once the acute attack has settled.

There are no guidelines for the initial medical treatment emergency treatment. An example regime would be:
  • combination of eye drops, for example:
    • a direct parasympathomimetic (e.g. pilocarpine, causes contraction of the ciliary muscle → opening the trabecular meshwork → increased outflow of the aqueous humour)
    • a beta-blocker (e.g. timolol, decreases aqueous humour production)
    • an alpha-2 agonist (e.g. apraclonidine, dual mechanism, decreasing aqueous humour production and increasing uveoscleral outflow)
  • intravenous acetazolamide
    • reduces aqueous secretions

Definitive management
  • laser peripheral iridotomy
    • creates a tiny hole in the peripheral iris → aqueous humour flowing to the angle