Primary Open Angle Glaucoma (POAG)

Question 1

What is the aetiology and risk factors of POAG?

Answer 1

Aetiology: Optic Nerve Head Damage

Risk Factors: Age, Hypertension, Family Hx, Ethnicity Hyperopia

Question 2

What are the two pathogenesis theories for POAG?

Answer 2

Mechanical Theory: High IOP mechanically forces the lamina cribrosa and axons on the ONH resulting in nerve fibre damage.

Vascular Theory: IOP causes ischaemia of nerve axons due to reduction of blood flow.

Question 3

What are the two pathogenesis theories for POAG?

Answer 3

Mechanical Theory: High IOP mechanically forces the lamina cribrosa and axons on the ONH resulting in nerve fibre damage.

Vascular Theory: IOP causes ischaemia of nerve axons due to reduction of blood flow.

Question 4

What are the signs of POAG?

Answer 4

CUP: deeper cup, larger C:D, asymmetry >0,2, lamina cribrosa.

NRR: Loss of ISNT, thinning

Vascular: Baring, Bayonetting, Disc haemorrhages, nasalisation of vessels

IOP (if >24mmHg):

Central cornea thickness greater than 550microns.

VF: Paracentral scotoma, Arcuate scotoma, Macula sparing (should all respect horizontal midline)

Question 5

What are the symptoms of POAG?

Answer 5

Asymptomatic

Question 6

What investigations would you do with a px with suspected POAG?

Answer 6

1. VF
2. OCT
3. Fundus photo
4. IOP
5. Direct/indirect ophthalmoscopy
6. Van Herrick’s

Question 7

What is the management for a px with POAG?

Answer 7

If IOP < 30 = routine referral or advice/monitor

If IOP > 30 = Urgent Referral

Question 8

What are the treatments for POAG?

Answer 8

If IOP < 30: Corticosteroid, Prostaglandins

If IOP > 30: Laser treatment i.e peripheral iris iridotomy or laser trabeculoplasty or surgery o.e. trabeculectomy

Question 9

What are the differential diagnosis for POAG?

Answer 9

Ocular hypertension
Tilted Discs
Physiological cupping
Pigment dispersion glaucoma
Pseudoexfoliation glaucoma
Steroid-induced glaucoma
Myopia