Acute angle closure glaucoma Flashcards
Pathophysiology?
In acute angle-closure glaucoma (AACG) there is a rise in IOP secondary to an impairment of aqueous outflow.
Predisposing factors?
- hypermetropia (long-sightedness)
- pupillary dilatation
- lens growth associated with age
Signs and symptoms?
- 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
What should you do on diagnosis?
Urgently refer to an ophthalmologist as this is an emergency
Which is given first medical or surgical treatment?
Emergency medical treatment is required to lower the IOP with more definitive surgical treatment given once the acute attack has settled.
How does a direct parasympathomimetic work?
Causes contraction of the ciliary muscle → opening the trabecular meshwork → increased outflow of the aqueous humour
Example of a parasympathomimetic?
Pilocarpine
How does a beta-blocker work?
Decreases aqueous humour production
Examples of beta-blockers used in treatment of this condition?
Timolol
How does a alpha-2 agonist work?
Dual mechanism: decreasing aqueous humour production and increasing uveoscleral outflow
Example of a alpha-2 agonist?
Apraclonidine
What does acetazolamide do and how is it prescribed?
Reduces aqueous secretions and is given IV
Definitive management?
Laser peripheral iridotomy
How does the definitive treatment work?
Laser peripheral iridotomy creates a tiny hole in the peripheral iris → aqueous humour flowing to the angle
