Wk 16: Glaucoma

Question 1

What is glaucoma?

Answer 1

Progressive damage to nerve leads to impaired vision + blindness

Question 2

What are the characteristics of glaucoma?

Answer 2

• Visual field defects
• Changes to the optic nerve head
• Nerve fibre layer defects

Question 3

What is ocular hypertension?

Answer 3

Consistently/recurrently elevated intraocular pressure + no sign of glaucoma

Question 4

What is intraocular pressure?

Answer 4

• Keeys eye in shape of globe
• Maintained by balance btw prod + outflow of aqueous humour
• Normally: 10-21 mmHg

Question 5

What is the intraocular pressure in acute angle closure glaucoma?

Answer 5

70 mmHg

Question 6

What is angle closure glaucoma?

Answer 6

Angle btw iris + cornea partially closed:
- Blocks trabecular meshwork + prevents drainage of intraocular fluid

• As fluid prod, pressure inc + optic nerve damaged
• Chronic/acute

Question 7

What is open angle glaucoma?

Answer 7

Angle btw iris + cornea open:
- Chronic

• IOP can be inc or w/in range
• Both eyes affected
• W/o treatment: asymptomatic, visual field defect when loss of optic nerve fibre
• Treatment: visual field defects

Question 8

When would you suspect acute ACG?

Answer 8

• Acute painful red eye
• Female
• Asian
• Long sighted
• Older

Question 9

What are the symptoms of acute ACG?

Answer 9

• Blurred vision
• Headache
• Adrenergic drugs or antimuscarinic
• Semi-dilated + fixed pupil
• Tender hard eye

Question 10

What is the management of acute ACG in emergency situations?

Answer 10

• 1 drop pilocarpine 2% blue eyes OR
• 1 drop pilocarpine 4% brown eyes
• AND single dose oral acetazolamide 500mg

Question 11

What is the management of acute ACG in secondary care?

Answer 11

• Topical + IV drugs red intraocular pressure + analgesia
• Surgery: aqueous humour flow from posterior chamber into anterior

Question 12

What are the risk factors of chronic OAG?

Answer 12

• Raised intraocular pressure
• Age
• Fx: first degree
• Black african
• Corticosteroid: inc outflow of aqueous humour
• Short sighted
• Diabetes

Question 13

What are the typical features of chronic OAG?

Answer 13

• Inc IOP
• Visual field defects
• Cupped optic disc

Question 14

What is the treatment for ocular hypertension in chronic OAG?

Answer 14

• Topical prostaglandin w/ 24 mmHg or risk of visual impairment
• Not tolerated: another topical prostaglandin or bblocker

Question 15

What is the treatment for advanced COAG?

Answer 15

• Surgery w/ augmentation (chemo)
• Topical prostaglandins + other topical IOP lowering agents
• Laser (trabeculectomy)

Question 16

What is the MOA of topical prostaglandins?

Answer 16

Lower IOP by inc uveoscleral outflow, inc outflow of aqueous humour

Question 17

What are examples of topical prostaglandins?

Answer 17

OD:
- Latanoprost

• Travoprost
• Bimatoprost

Question 18

What are the adverse effects of topical prostaglandins?

Answer 18

Local:
- Inc brown pigmentation

• Darkening, thickening + lengthening of lashes
• Blepharitis
• Ocular pain + irritation

Systemic:
- Dyspnoea, asthma

• Dizzy, headache

Question 19

What is the MOA of topical beta blockers + examples

Answer 19

Lower IOP by red aqueous prod:
- Betaxolol

• Carteolol
• Timolol
• OD/BD

Question 20

What are the adverse effects of topical b-blockers?

Answer 20

• Local: stinging, burning, itching
• Systemic: bradycardia, sleep disturbance, hallucination

Question 21

What is the MOA of topical sympathomimetics and give an example?

Answer 21

Red IOP by dec aqueous prod + inc aqueous drainage
- Brimonidine tartrate 0/2%

• One drop BD, 12 hrs apart

Question 22

What are the adverse effects of topical sympathomimetics?

Answer 22

• Local: stinging, dry mouth + abnormal taste in mouth
• Interaction: alcohol, barbiturates, opiates, sedatives + anaesthetics

Question 23

What is the MOA of carbonic anhydrase inhibitors and give an example?

Answer 23

Red IOP by red secretion of aqueous humour:
- Topical: Brinzolamide/Dorzolamide BD/TDS

• Oral: Acetazolamide 0.25g-1g daily

Question 24

What are the adverse effects of carbonic anhydrase inhibitors?

Answer 24

• Local: blepharitis/eye irritation, pain, dryness
• Systemic: non in topical

Question 25

What are the interactions of carbonic anhydrase inhibitors?

Answer 25

• Aspirin: acetazolamide = metabolic acidosis
• Anticonvulsant: acetazolamide modifies metabolism
• Ciclosporin: rapid inc in serum cyclosporine levels + renal toxicity

Question 26

What is the MOA of topical miotics + give an example?

Answer 26

• Inc flow of aqueous humour from eye
• Pilocarpine: 1 drop QDS
• Pilogel: 1 drop nocte

Question 27

What are the local adverse effects of topical miotics?

Answer 27

• Burning, itching
• Brow ache
• Conjunctival vascular congestion
• Vitreous haemorrhage
• Retinal detachment

Question 28

What are the patient counselling points for COAG?

Answer 28

• Wash hands
• Remove contact lense before applying
• Shake before each use
• 5 mins btw each prep: drops, gels then ointment
• Minimise systemic abs: close eyes after administering, press tear duct against nose for 1 min
• Replace after 4 wks
• If visual field affects both eyes inform DVLA
• If itchy eyes, inform doctor

Question 29

Which eye drop requires refrigerator storage before opening?

Answer 29

Latanoprost, once opened keep in cool place for 4 wks