Open Angle Glaucoma

Question 1

What is a glaucoma?

Answer 1

Optic nerve damage that is caused by a significant rise in IOP which is caused by a blockage in the aqueous humour

Question 2

What are the 2 types of glaucoma?

Answer 2

Open Angle and Closed Angle

Question 3

What is the pathophysiology of open-angle glaucoma?

Answer 3

• Gradual increase in resistance through the trabecular meshwork making it more difficult for aqueous humour to flow through the meshwork and exit the eye and so the pressure builds gradually -> chronic

Question 4

What is the difference between open angle and closed angle glaucoma?

Answer 4

• In open, the angle between the iris and the cornea is normal whereas in closed, it is atleast partially reduced

Question 5

What is cupping of the optic disc?

Answer 5

• In the optic disc, there is a normal small indent known as the optic cup
• When pressure in the eye increases, the indent becomes larger and deeper (greater than 0.5 of the size of the optic disc is abnormal)

Question 6

What are the risk factors for open angle glaucoma?

Answer 6

• Increasing age
• Family history
• Black ethnic origin
• Near-sightedness (myopia)

Question 7

How does open-angle glaucoma present?

Answer 7

• Often asymptomatic for a long time
• Diagnosed at optometry usually
• If symptomatic, affects peripheral vision first eventually leading to tunnel vision
• Gradual onset of pain, headaches, blurred vision and halos around the eyes at night also present

Question 8

How do you measure intraocular pressure?

Answer 8

1. Non-contact tonometry used commonly
2. Goldmann applanation tonometry is the gold standard

Question 9

What are the investigations for OA glaucoma?

Answer 9

• GAT
• Fundoscopy
• Visual field assessment

Question 10

What is the management of open-angle glaucoma?

Answer 10

• Aim is to reduce intraocular pressure
• Selective laser trabeculoplasty should be offered to those with IOP > 24
• Second line: Prostaglandin analogue drops e.g. latanoprost which help with outflow
• Other options include topical carbonic anhydrase inhibitors e.g.. dorzolamide or topical beta blocker e.g. timolol