Chronic Open Angle Glaucoma (1)

Question 1

What is Glaucoma?

What is the pathophysiology in Chronic/Open Angle Glaucoma?

What are its risk factors?

Answer 1

➊ Optic nerve damage that is caused by a rise in intraocular pressure, which is caused by a blockage in the drainage of aqueous humour

➋ Gradual increase in the resistance of the trabecular meshwork, therefore making it harder for the aqueous humour to flow through it and drain out = Slow increase in pressure

➌ • Raised IOP
• DM
• HTN
• Increasing age
• FHx
• Near-sightedness (Myopia)

Question 2

How does the vision loss present?
→ Why are most unaware of this visual field defect in the early stages?

What else does it present with?

What is seen O/E?
→ What is Cupping?

Answer 2

N.B. Usually asymptomatic for a long time, therefore diagnosed during routine eye tests

➊ Gradual loss of peripheral vision, which eventually becomes tunnel vision
→ Their other eye compensates quite well

➋ Gradual onset of fluctuating pain, headaches, blurred vision and halos around lights

➌ Pale optic disc (optic nerve atrophy), Optic disc cupping
→ Sign of Raised Intraocular Pressure – The cup is the small indent in the optic disc. When there’s increased pressure, the size of this cup increases as it becomes wider and deeper (An optic cup > 50% of the optic disc is abnormal).

Question 3

Measuring Intraocular Pressure:
What is the Gold standard tool for this?

What else can be used?

Answer 3

➊ Goldmann Applanation Tonometry – Pressure applied to cornea – More accurate

➋ Non-contact Tonometry – Shooting a puff of air at the cornea and measuring the corneal response to it – Less accurate but gives a helpful estimate during general screening

Question 4

What is needed for a diagnosis? What is checked for in each?

Answer 4

• Goldmann Applanation Tonometry – Check IOP
• Fundoscopy – Check for cupping
• Eye examination – Check for peripheral vision loss

Question 5

Management:
When is treatment usually started?

What is the 1st line treatment option?

What are the 2nd line options?

Answer 5

➊ When IOP is > 24 mmHg and risk of visual impairment

➋ Selective Laser Trabeculoplasty (SLT) – Laser directed at certain cells in the trabecular network, therefore improving drainage

➌ Prostaglandin eye drops (e.g. Latanoprost), B-blockers, CA inhibitors

N.B. One SE of Latanoprost is increased eyelash growth