Acute Glaucoma

Question 1

What is Glaucoma

Answer 1

Glaucoma refers to the optic nerve damage that is caused by a significant rise in intraocular pressure. The raised intraocular pressure is caused by a blockage in aqueous humour trying to escape the eye.

Question 2

Acute Angle Closure Glaucoma occurs when?

Answer 2

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.

Question 3

Acute Angle Closure Glaucoma risk factors

Answer 3

Increasing age
Females are affected around 4 times more often than males
Family history
Chinese and East Asian ethnic origin. Unlike open-angle glaucoma, it is rare in people of black ethnic origin.
Shallow anterior chamber
Adrenergic medications such as noradrenalin
Anticholinergic medications such as oxybutynin and solifenacin
Tricyclic antidepressants such as amitriptyline, which have anticholinergic effects

Question 4

Acute Angle Closure Glaucoma Present

Answer 4

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

Question 5

Acute Angle Closure Glaucoma Present

Answer 5

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

Question 6

Acute Angle Closure Glaucoma Examination

Answer 6

Red-eye
Teary
Hazy cornea
Decreased visual acuity
Dilatation of the affected pupil
Fixed pupil size
Firm eyeball on palpation

Question 7

Acute Angle Closure Glaucoma treatment?

Answer 7

Lie patient on their back without a pillow
Give pilocarpine eye drops (2% for blue, 4% for brown eyes)
Give acetazolamide 500 mg orally
Given analgesia and an antiemetic if required

Question 8

What is pilocarpine?

Answer 8

Pilocarpine acts on the muscarinic receptors in the sphincter muscles in the iris and causes constriction of the pupil. Therefore it is a miotic agent. It also causes ciliary muscle contraction. These two effects cause the pathway for the flow of aqueous humour from the ciliary body, around the iris and into the trabecular meshwork to open up.

Question 9

What is acetazolamide?

Answer 9

Acetazolamide is a carbonic anhydrase inhibitor. This reduces the production of aqueous humour.

Question 10

Secondary care management of Acute Glaucoma?

Answer 10

Pilocarpine
Acetazolamide (oral or IV)
Hyperosmotic agents such as glycerol or mannitol increase the osmotic gradient between the blood and the fluid in the eye
Timolol is a beta-blocker that reduces the production of aqueous humour
Dorzolamide is a carbonic anhydrase inhibitor that reduces the production of aqueous humour
Brimonidine is a sympathomimetic that reduces the production of aqueous fluid and increase uveoscleral outflow

Laser iridotomy is usually required as a definitive treatment. This involves using a laser to make a hole in the iris to allow the aqueous humour to flow from the posterior chamber into the anterior chamber. The relieves pressure that was pushing the iris against the cornea and allows the humour the drain.