Glaucoma

Question 1

What is glaucoma?

Answer 1

Group of diseases characterised by progressive optic nerve damage + visual field loss
Thought to be due to raised intra-ocular pressure (IOP)

Question 2

Describe the pathophysiology of glaucoma?

Answer 2

Blockage of aqueous outflow –> raised IOP –> damage + loss of retinal nerve fibres at optic disc –> visual field loss

Question 3

Which angle is implicated in open vs closed angle glaucoma?

Answer 3

Angle between iris and cornea

Question 4

What happens in acute angle closure glaucoma?

Answer 4

Closure of the angle by iris causes a sudden rise in IOP

–> emergency

Question 5

Which type of patients are most likely to get acute angle closure glaucoma?

Answer 5

Elderly hypermetropic (long sighted - thick glasses)

Question 6

What are the symptoms of acute angle closure glaucoma?

Answer 6

Painful, red eye
Sudden visual loss
Visual halo
Headache, nausea + vomiting

Question 7

What are the signs of acute angle closure glaucoma?

Answer 7

Red eye
Cloudy/hazy cornea
Fixed, mid-dilated pupil
Raised IOP (50-80mmHg)

Question 8

What is the immediate management of acute angle closure glaucoma?

Answer 8

IV/oral Acetazolamide (Diamox)
Topical antihypertensive drops
Topical steroids
Pilocarpine drops
Analgesia + anti-emetic

Question 9

What is the definitive management of acute open angle glaucoma?

Answer 9

Peripheral Iridotomy (PI) - surgical or laser
--> allows aqueous humour to flow freely from posterior to anterior chamber, reducing chance of recurrence

Question 10

What causes primary open angle glaucoma (POAG)?

Answer 10

Blocked drainage of aqueous –> raised IOP

Question 11

What are the symptoms of POAG?

Answer 11

Usually none –> most detected by optometrist at routine examination

Question 12

What are the risk factors for POAG?

Answer 12

Age
Raised IOP
Family history
Afro-Caribbean origin

Question 13

What is the usual progression of POAG?

Answer 13

Initially atrophy of peripheral rim of optic nerve –> reduced peripheral vision
Continued damage to nerve –> additional loss of central vision

Question 14

Which examinations should be done for POAG?

Answer 14

Tonometry (assess IOP)
Visual field testing
Fundoscopy

Question 15

What would be seen on fundoscopy in POAG?

Answer 15

Thin outer rim of nerve –> cupping

looks like a donut

Question 16

What is the aim of treatment for POAG?

Answer 16

Lower IOP to a level that prevents further nerve damage

Question 17

What is the usual order of treatment for POAG?

Answer 17

Prostaglandin
Beta-blocker
Trusopt/alphagan
Surgery

Question 18

What do prostaglandins do in the treatment of POAG and give an example?

Answer 18

Increase outflow of aqueous humour

- Xalatan drops

Question 19

What do beta-blockers do in the treatment of POAG and give an example?

Answer 19

Reduce aqueous secretion

- Timoptol, laevobutanol drops

Question 20

What are the surgical options for POAG?

Answer 20

Trabeculectomy:
- aim to make guarded fistula into anterior chamber
Trabeculoplasty:
- laser fired at trabecular meshwork to increased outflow of aqueous

Question 21

How are carbonic anhydrase inhibitors used in the treatment of glaucoma?

Answer 21

Topical Dorzolamide (Trusopt) --> POAG
Systemic Acetazolamide (Diamox) --> acute angle closure glaucoma

Question 22

Why is Acetazolamide used for acute angle closure glaucoma but not POAG?

Answer 22

It is very good at lowering IOP but can only be used short term due to side effects:
- paraesthesia, peri-oral tingling + renal calculi

Question 23

What do pilocarpine drops do in the treatment of POAG?

Answer 23

Increased aqueous outflow

Question 24

What are the side effects of pilocarpine drops?

Answer 24

Few systemic side effects
Local side effects:
- pupil constriction
- pain
- dim vision
- problems seeing at night