Ophthalmology - Acute Angle-Closure Glaucoma

Question 1

What happens in acute angle closure glaucoma?

Answer 1

Iris bulges forward and seals off the trabecular meshwork from the anterior chamber

Prevents aqeuous humour draining, causes a continual increase in intraocular pressure

Pressure builds up in posterior chamber pushing iris forward and exacerbates angle closure

Question 2

What is the significance of acute angle closure glaucoma?

Answer 2

Ophthalmological emergency
Needs rapid treatment to prevent permanent vision loss.

Question 3

What are the risk factors for acute angle-closure glaucoma?

Answer 3

• Increasing age
• Family history
• Female (four times more likely than males)
• Chinese and East Asian ethnic origin
• Shallow anterior chamber

Question 4

What is the difference in risk factors between angle-closure and open-angle glaucoma in black people?

Answer 4

Open-angle glaucoma
More common in black people

Angle-closure glaucoma
Rare

Question 5

What medications can precipitate acute angle-closure glaucoma?

Answer 5

• Adrenergic medications (e.g., noradrenaline)
• Anticholinergic medications (e.g., oxybutynin and solifenacin)
• Tricyclic antidepressants (e.g., amitriptyline) they have anticholinergic effects

Question 6

How does a patient with acute angle-closure glaucoma present?

Answer 6

• Severely painful red eye
• Blurred vision
• Halos around lights
• Associated headache, nausea and vomiting

Question 7

What signs can be observed on examination of acute angle-closure glaucoma?

Answer 7

• Red eye
• Hazy cornea
• Decreased visual acuity
• Mid-dilated pupil
• Fixed-size pupil
• Hard eyeball on gentle palpation

Question 8

What initial management steps should be taken for acute angle-closure glaucoma?

Answer 8

• Lying the patient on their back without a pillow
• Pilocarpine eye drops (2% for blue and 4% for brown eyes)
• Acetazolamide 500 mg orally
• Analgesia and an antiemetic, if required

Question 9

What is the mechanism of action of pilocarpine in acute angle-closure glaucoma?

Answer 9

Acts on muscarinic receptors in the sphincter muscles in the iris

Causing pupil constriction and ciliary muscle contraction to open the pathway for aqueous humour flow

Question 10

What is the function of acetazolamide in the treatment of acute angle-closure glaucoma?

Answer 10

It is a carbonic anhydrase inhibitor that reduces the production of aqueous humour

Question 11

What medical options for secondary care management of acute angle-closure glaucoma?

Answer 11

• Pilocarpine eye drops
• Acetazolamide (oral or intravenous)
• Hyperosmotic agents (e.g., intravenous mannitol)
• Timolol
• Dorzolamide
• Brimonidine

Question 12

What is the definitve treatment for acute angle-closure glaucoma?

Answer 12

Laser iridotomy

Involves making a hole in the iris using a laser to allow aqueous humour to flow from the posterior chamber to the anterior chamber, relieving pressure

Opens pathway for aqueous humour to drain