acute angle closure glaucoma (AACG)

Question 1

what happens in AACG?

Answer 1

there is a rise in IOP 2˚ to an impairment of aqueous outflow

Question 2

what are factors predisposing to AACG?

Answer 2

• hypermetropia (long-sightedness)
• pupillary dilatation
• lens growth restricted with age

Question 3

what are the features of AACG?

Answer 3

• severe pain: ocular / headache
• decreased visual acuity
• hard, red eye
• haloes around lights
• semi-dilated non-reacting pupil
• corneal oedema resulting in dull/hazy cornea
• systemic upset e.g. N+V, abdo pain

Question 4

how do you manage AACG?

Answer 4

an emergency ⇒ urgent referral to ophthalmologist

emergency medical rx to lower IOP with more definitive surgical rx once acute attack has settled

Question 5

what is included in the emergency medical rx for AACG?

Answer 5

1. combination of eye drops e.g. pilocarpine, timolol, apraclonidine
2. IV acetazolamide

Question 6

what is pliocarpine?

Answer 6

a direct parasympathomimetic

causes contraction of the ciliary muscle ⇒ opens trabecular meshwork ⇒ increased outflow of aqueous humour

Question 7

what is timolol?

Answer 7

a beta-blocker

decreases aqueous humour production

Question 8

what is apraclonidine?

Answer 8

an alpha-2 agonist

dual mechanism, decreases aqueous humour production and increases uveoscleral outflow

Question 9

what does IV acetazolamide do?

Answer 9

reduces aqueous secretions

Question 10

what is the definitive mx for AACG?

Answer 10

laser peripheral iridotomy

Question 11

what does laser peripheral iridotomy do?

Answer 11

creates a tiny hole in the peripheral iris ⇒ aqueous humour flows to the angle

Question 12

what is AACG associated with?

Answer 12

hypermetropia (long-sightedness)

small eyes = shallower anterior chambers = narrower angles

Question 13

what are the key side effects of prostaglandin analogues e.g. Latanoprost?

Answer 13

• increased eyelash length
• iris pigmentation
• periocular pigmentation

Question 14

in pts with a hx of asthma, what should be used first-line to treat glaucoma?

Answer 14

prostaglandin analogues e.g. Latanoprost

Question 15

A 83-year-old man is brought to the emergency department by his daughter. He is complaining of a 2-hour history of a severe headache around his left eye, significant nausea and a few episodes of vomiting. He also reports that his vision is blurred and that he is seeing halos with bright lights.

Examination reveals his left pupil is semi-dilated and non reactive. There is no evidence of papilloedema.

Based on the most likely diagnosis, what is the most definitive treatment once this patient’s condition is stable?

Answer 15

Laser peripheral iridotomy is the definitive treatment for acute angle-closure glaucoma

Question 16

what are the treatment aims for AACG?

Answer 16

1. lower IOP and prevent rapid deterioration to visual loss
   - BB e.g. timolol and IV acetazolamide to reduce aqueous production
   - parasympathomimetics (e.g. pilocarpine) to induce miosis and reduce angle closure
2. treat closed angle once pt is stable
   - laser peripheral iridotomy