Glaucoma

Question 1

What is glaucoma?

Answer 1

A group of chronic diseases characterised by a progressive optic neuropathy resulting in characteristic field defects

Question 2

What are some risk factors associated with glaucoma?

Answer 2

Raised intraocular pressure
Increased age

Question 3

How does glaucoma occur?

Answer 3

1. Normally, fluid drains out through the trabecular meshwork and into the Canal of Schlemm
2. In glaucoma, one of these becomes blocked, raising intraocular pressure
3. This has an effect on the optic disc and nerve

Question 4

What is meant by open-angled glaucoma?

Answer 4

Glaucoma caused by poor drainage through the trabecular meshwork

Question 5

What is meant by closed-angle glaucoma?

Answer 5

Glaucoma caused by patency of the meshwork or canal, which further pushes the iris forward and closes the angle containing the drainage mechanism

Question 6

What is meant by robotic glaucoma?

Answer 6

New vessel formation in diabetic eye disease forms obstructive angle (rare and late complication)

Question 7

What is shown?

Answer 7

Rubeotic glaucoma

Question 8

How does closed-angle glaucoma present?

Answer 8

1/3 present as an emergency - acute red eye and visual loss with headache and N+V

Question 9

What are some signs of closed-angle glaucoma?

Answer 9

red eye, cloudy cornea, dilated pupil

Question 10

What is shown?

Answer 10

Closed-angle glaucoma

Question 11

What are some symptoms of open-angle glaucoma?

Answer 11

• Usually asymptomatic
• Screened for by optometrists

Question 12

What are some signs of open-angle glaucoma?

Answer 12

• Arcuate visual field defect (Pattern of visual field defect corresponds to nerve fibre arrangement)
• May or may not have high IOP

Question 13

What will be seen on fundoscopy in glaucoma?

Answer 13

Cupped disc (increased cup-to-disc ratio) indicates a reduced volume of healthy neuro-retinal tissue, which can occur in glaucoma

A pale optic disc suggests the presence of optic atrophy, which can result from advanced glaucoma

Question 14

What causes disc cupping in glaucoma?

Answer 14

• Raised intraocular pressure damages the optic disc and nerve
• The edges of the disc become rolled up and the centre becomes depressed

Question 15

What is shown?

Answer 15

Disc cupping in glaucoma

Question 16

How is primary open-angled glaucoma managed?

Answer 16

• Prostanoids e.g. latanoprost (‘xalatan’) - Causes browning of surrounding structures - first line
• Second line - β blockers, carbonic anhydrase inhibitors
• Others - ⍺2 adrenergic agonist, parasympathomimetics, combination eyedrops (e.g. cosopt - dorxolamide and timolol)

Question 17

How do glaucoma drops work?

Answer 17

Either by decreasing aqueous production or increasing drainage

Question 18

How is closed-angle glaucoma managed?

Answer 18

• In acute presentation need to lower IOP quickly with drops/oral medication to prevent the patient from going blind
• Definative management - laser peripheral iridotomy